Polymers functionalized with polycyano compounds

ABSTRACT

A method for preparing a functionalized polymer, the method comprising the steps of polymerizing monomer to form a reactive polymer, and reacting the reactive polymer with a polycyano compound.

This application is a divisional application of U.S. Non-Provisionalapplication Ser. No. 13/146,042, filed on which claims the benefit ofInternational Application Serial No. PCT/US2010/021783, filed on Jan.22, 2010, and U.S. Provisional Application Ser. No. 61/146,893, filedJan. 23, 2009, which is incorporated herein by reference.

FIELD OF THE INVENTION

One or more embodiments of the present invention relate to polymersfunctionalized with polycyano compounds and methods for theirmanufacture.

BACKGROUND OF THE INVENTION

In the art of manufacturing tires, it is desirable to employ rubbervulcanizates that demonstrate reduced hysteresis, i.e., less loss ofmechanical energy to heat. For example, rubber vulcanizates that showreduced hysteresis are advantageously employed in tire components, suchas sidewalls and treads, to yield tires having desirably low rollingresistance. The hysteresis of a rubber vulcanizate is often attributedto the free polymer chain ends within the crosslinked rubber network, aswell as the dissociation of filler agglomerates.

Functionalized polymers have been employed to reduce the hysteresis ofrubber vulcanizates. The functional group of the functionalized polymermay reduce the number of free polymer chain ends via interaction withfiller particles. Also, the functional group may reduce filleragglomeration. Nevertheless, whether a particular functional groupimparted to a polymer can reduce hysteresis is often unpredictable.

Functionalized polymers may be prepared by post-polymerization treatmentof reactive polymers with certain functionalizing agents. However,whether a reactive polymer can be functionalized by treatment with aparticular functionalizing agent can be unpredictable. For example,functionalizing agents that work for one type of polymer do notnecessarily work for another type of polymer, and vice versa.

Lanthanide-based catalyst systems are known to be useful forpolymerizing conjugated diene monomers to form polydienes having a highcontent of cis-1,4 linkage. The resulting cis-1,4-polydienes may displaypseudo-living characteristics in that, upon completion of thepolymerization, some of the polymer chains possess reactive ends thatcan react with certain functionalizing agents to yield functionalizedcis-1,4-polydienes.

The cis-1,4-polydienes produced with lanthanide-based catalyst systemstypically have a linear backbone, which is believed to provide bettertensile properties, higher abrasion resistance, lower hysteresis, andbetter fatigue resistance as compared to the cis-1,4-polydienes preparedwith other catalyst systems such as titanium-, cobalt-, and nickel-basedcatalyst systems. Therefore, the cis-1,4-polydienes made withlanthanide-based catalysts are particularly suitable for use in tirecomponents such as sidewalls and treads. However, one disadvantage ofthe cis-1,4-polydienes prepared with lanthanide-based catalysts is thatthe polymers exhibit high cold flow due to their linear backbonestructure. The high cold flow causes problems during storage andtransport of the polymers and also hinders the use of automatic feedingequipment in rubber compound mixing facilities.

Anionic initiators are known to be useful for the polymerization ofconjugated diene monomers to form polydienes having a combination of1,2-, cis-1,4- and trans-1,4-linkages. Anionic initiators are alsouseful for the copolymerization of conjugated diene monomers withvinyl-substituted aromatic compounds. The polymers prepared with anionicinitiators may display living characteristics in that, upon completionof the polymerization, the polymer chains possess living ends that arecapable of reacting with additional monomers for further chain growth orreacting with certain functionalizing agents to give functionalizedpolymers. Without the introduction of any coupled or branchedstructures, the polymers prepared with anionic initiators may alsoexhibit the problem of high cold flow.

Because functionalized polymers are advantageous, especially in themanufacture of tires, there exists a need to develop new functionalizedpolymers that give reduced hysteresis and reduced cold flow.

SUMMARY OF THE INVENTION

One or more embodiments of the present invention provide a method forpreparing a functionalized polymer, the method comprising the steps ofpolymerizing monomer to form a reactive polymer; and reacting thereactive polymer with a polycyano compound.

Other embodiments of the present invention provide a functionalizedpolymer prepared by the steps of polymerizing monomer to form a reactivepolymer and reacting the polymer with a polycyano compound.

Other embodiments of the present invention provide a functionalizedpolymer defined by at least one of the formulae:

where π is a polymer chain and R¹ is a divalent organic group.

Other embodiments of the present invention provide a functionalizedpolymer defined by at least one of the formulae:

where π is a polymer chain and R¹ is a divalent organic group.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graphical plot of cold-flow gauge (mm at 8 min) versusMooney viscosity (ML 1+4 at 100° C.) for functionalizedcis-1,4-polybutadiene prepared according to one or more embodiments ofthe present invention as compared to unfunctionalizedcis-1,4-polybutadiene.

FIG. 2 is a graphical plot of hysteresis loss (tan δ) versus Mooneyviscosity (ML 1+4 at 130° C.) for vulcanizates prepared fromfunctionalized cis-1,4-polybutadiene prepared according to one or moreembodiments of the present invention as compared to vulcanizatesprepared from unfunctionalized cis-1,4-polybutadiene.

FIG. 3 is a graphical plot of cold-flow gauge (mm at 30 min) versusMooney viscosity (ML 1+4 at 100° C.) for functionalizedpoly(styrene-co-butadiene) prepared according to one or more embodimentsof the present invention as compared to unfunctionalizedpoly(styrene-co-butadiene).

FIG. 4 is a graphical plot of hysteresis loss (tan δ) versus Mooneyviscosity (ML 1+4 at 130° C.) for vulcanizates prepared fromfunctionalized poly(styrene-co-butadiene) prepared according to one ormore embodiments of the present invention as compared to vulcanizateprepared from unfunctionalized poly(styrene-co-butadiene).

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

According to one or more embodiments of the present invention, areactive polymer is prepared by polymerizing conjugated diene monomerand optionally monomer copolymerizable therewith, and this reactivepolymer is then functionalized by reaction with a polycyano compound.The resultant functionalized polymers can be used in the manufacture oftire components. In one or more embodiments, the resultantfunctionalized polymers exhibit advantageous cold-flow resistance andprovide tire components that exhibit advantageously low hysteresis.

Examples of conjugated diene monomer include 1,3-butadiene, isoprene,1,3-pentadiene, 1,3-hexadiene, 2,3-dimethyl-1,3-butadiene,2-ethyl-1,3-butadiene, 2-methyl-1,3-pentadiene, 3-methyl-1,3-pentadiene,4-methyl-1,3-pentadiene, and 2,4-hexadiene. Mixtures of two or moreconjugated dienes may also be utilized in copolymerization.

Examples of monomer copolymerizable with conjugated diene monomerinclude vinyl-substituted aromatic compounds such as styrene,p-methylstyrene, α-methylstyrene, and vinylnaphthalene.

In one or more embodiments, the reactive polymer is prepared bycoordination polymerization, wherein monomer is polymerized by using acoordination catalyst system. The key mechanistic features ofcoordination polymerization have been discussed in books (e.g., Kuran,W., Principles of Coordination Polymerization; John Wiley & Sons: NewYork, 2001) and review articles (e.g., Mulhaupt, R., MacromolecularChemistry and Physics 2003, volume 204, pages 289-327). Coordinationcatalysts are believed to initiate the polymerization of monomer by amechanism that involves the coordination or complexation of monomer toan active metal center prior to the insertion of monomer into a growingpolymer chain. An advantageous feature of coordination catalysts istheir ability to provide stereochemical control of polymerizations andthereby produce stereoregular polymers. As is known in the art, thereare numerous methods for creating coordination catalysts, but allmethods eventually generate an active intermediate that is capable ofcoordinating with monomer and inserting monomer into a covalent bondbetween an active metal center and a growing polymer chain. Thecoordination polymerization of conjugated dienes is believed to proceedvia π-allyl complexes as intermediates. Coordination catalysts can beone-, two-, three- or multi-component systems. In one or moreembodiments, a coordination catalyst may be formed by combining a heavymetal compound (e.g., a transition metal compound or alanthanide-containing compound), an alkylating agent (e.g., anorganoaluminum compound), and optionally other co-catalyst components(e.g., a Lewis acid or a Lewis base). In one or more embodiments, theheavy metal compound may be referred to as a coordinating metalcompound.

Various procedures can be used to prepare coordination catalysts. In oneor more embodiments, a coordination catalyst may be formed in situ byseparately adding the catalyst components to the monomer to bepolymerized in either a stepwise or simultaneous manner. In otherembodiments, a coordination catalyst may be preformed. That is, thecatalyst components are pre-mixed outside the polymerization systemeither in the absence of any monomer or in the presence of a smallamount of monomer. The resulting preformed catalyst composition may beaged, if desired, and then added to the monomer that is to bepolymerized.

Useful coordination catalyst systems include lanthanide-based catalystsystems. These catalyst systems may advantageously producecis-1,4-polydienes that, prior to quenching, have reactive chain endsand may be referred to as pseudo-living polymers. While othercoordination catalyst systems may also be employed, lanthanide-basedcatalysts have been found to be particularly advantageous, andtherefore, without limiting the scope of the present invention, will bediscussed in greater detail.

Practice of the present invention is not necessarily limited by theselection of any particular lanthanide-based catalyst system. In one ormore embodiments, the catalyst systems employed include (a) alanthanide-containing compound, (b) an alkylating agent, and (c) ahalogen source. In other embodiments, a compound containing anon-coordinating anion or a non-coordinating anion precursor can beemployed in lieu of a halogen source. In these or other embodiments,other organometallic compounds, Lewis bases, and/or catalyst modifierscan be employed in addition to the ingredients or components set forthabove. For example, in one embodiment, a nickel-containing compound canbe employed as a molecular weight regulator as disclosed in U.S. Pat.No. 6,699,813, which is incorporated herein by reference.

As mentioned above, the lanthanide-based catalyst systems employed inthe present invention can include a lanthanide-containing compound.Lanthanide-containing compounds useful in the present invention arethose compounds that include at least one atom of lanthanum, neodymium,cerium, praseodymium, promethium, samarium, europium, gadolinium,terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, anddidymium. In one embodiment, these compounds can include neodymium,lanthanum, samarium, or didymium. As used herein, the term “didymium”shall denote a commercial mixture of rare-earth elements obtained frommonazite sand. In addition, the lanthanide-containing compounds usefulin the present invention can be in the form of elemental lanthanide.

The lanthanide atom in the lanthanide-containing compounds can be invarious oxidation states including, but not limited to, the 0, +2, +3,and +4 oxidation states. In one embodiment, a trivalentlanthanide-containing compound, where the lanthanide atom is in the +3oxidation state, can be employed. Suitable lanthanide-containingcompounds include, but are not limited to, lanthanide carboxylates,lanthanide organophosphates, lanthanide organophosphonates, lanthanideorganophosphinates, lanthanide carbamates, lanthanide dithiocarbamates,lanthanide xanthates, lanthanide β-diketonates, lanthanide alkoxides oraryloxides, lanthanide halides, lanthanide pseudo-halides, lanthanideoxyhalides, and organolanthanide compounds.

In one or more embodiments, the lanthanide-containing compounds can besoluble in hydrocarbon solvents such as aromatic hydrocarbons, aliphatichydrocarbons, or cycloaliphatic hydrocarbons. Hydrocarbon-insolublelanthanide-containing compounds, however, may also be useful in thepresent invention, as they can be suspended in the polymerization mediumto form the catalytically active species.

For ease of illustration, further discussion of usefullanthanide-containing compounds will focus on neodymium compounds,although those skilled in the art will be able to select similarcompounds that are based upon other lanthanide metals.

Suitable neodymium carboxylates include, but are not limited to,neodymium formate, neodymium acetate, neodymium acrylate, neodymiummethacrylate, neodymium valerate, neodymium gluconate, neodymiumcitrate, neodymium fumarate, neodymium lactate, neodymium maleate,neodymium oxalate, neodymium 2-ethylhexanoate, neodymium neodecanoate(a.k.a., neodymium versatate), neodymium naphthenate, neodymiumstearate, neodymium oleate, neodymium benzoate, and neodymiumpicolinate.

Suitable neodymium organophosphates include, but are not limited to,neodymium dibutyl phosphate, neodymium dipentyl phosphate, neodymiumdihexyl phosphate, neodymium diheptyl phosphate, neodymium dioctylphosphate, neodymium bis(1-methylheptyl)phosphate, neodymiumbis(2-ethylhexyl)phosphate, neodymium didecyl phosphate, neodymiumdidodecyl phosphate, neodymium dioctadecyl phosphate, neodymium dioleylphosphate, neodymium diphenyl phosphate, neodymiumbis(p-nonylphenyl)phosphate, neodymium butyl(2-ethylhexyl)phosphate,neodymium(1-methylheptyl)(2-ethylhexyl)phosphate, andneodymium(2-ethylhexyl)(p-nonylphenyl)phosphate.

Suitable neodymium organophosphonates include, but are not limited to,neodymium butyl phosphonate, neodymium pentyl phosphonate, neodymiumhexyl phosphonate, neodymium heptyl phosphonate, neodymium octylphosphonate, neodymium(1-methylheptyl)phosphonate,neodymium(2-ethylhexyl)phosphonate, neodymium decyl phosphonate,neodymium dodecyl phosphonate, neodymium octadecyl phosphonate,neodymium oleyl phosphonate, neodymium phenyl phosphonate,neodymium(p-nonylphenyl)phosphonate, neodymium butyl butylphosphonate,neodymium pentyl pentylphosphonate, neodymium hexyl hexylphosphonate,neodymium heptyl heptylphosphonate, neodymium octyl octylphosphonate,neodymium(1-methylheptyl)(1-methylheptyl)phosphonate,neodymium(2-ethylhexyl)(2-ethylhexyl)phosphonate, neodymium decyldecylphosphonate, neodymium dodecyl dodecylphosphonate, neodymiumoctadecyl octadecylphosphonate, neodymium oleyl oleylphosphonate,neodymium phenyl phenylphosphonate,neodymium(p-nonylphenyl)(p-nonylphenyl)phosphonate, neodymiumbutyl(2-ethylhexyl)phosphonate, neodymium(2-ethylhexyl)butylphosphonate,neodymium(1-methylheptyl)(2-ethylhexyl)phosphonate,neodymium(2-ethylhexyl)(1-methylheptyl)phosphonate,neodymium(2-ethylhexyl)(p-nonylphenyl)phosphonate, andneodymium(p-nonylphenyl)(2-ethylhexyl)phosphonate.

Suitable neodymium organophosphinates include, but are not limited to,neodymium butylphosphinate, neodymium pentylphosphinate, neodymiumhexylphosphinate, neodymium heptylphosphinate, neodymiumoctylphosphinate, neodymium(1-methylheptyl)phosphinate,neodymium(2-ethylhexyl)phosphinate, neodymium decylphosphinate,neodymium dodecylphosphinate, neodymium octadecylphosphinate, neodymiumoleylphosphinate, neodymium phenylphosphinate,neodymium(p-nonylphenyl)phosphinate, neodymium dibutylphosphinate,neodymium dipentylphosphinate, neodymium dihexylphosphinate, neodymiumdiheptylphosphinate, neodymium dioctylphosphinate, neodymiumbis(1-methylheptyl)phosphinate, neodymium bis(2-ethylhexyl)phosphinate,neodymium didecylphosphinate, neodymium didodecylphosphinate, neodymiumdioctadecylphosphinate, neodymium dioleylphosphinate, neodymiumdiphenylphosphinate, neodymium bis(p-nonylphenyl)phosphinate, neodymiumbutyl (2-ethylhexyl)phosphinate,neodymium(1-methylheptyl)(2-ethylhexyl)phosphinate, andneodymium(2-ethylhexyl)(p-nonylphenyl)phosphinate.

Suitable neodymium carbamates include, but are not limited to, neodymiumdimethylcarbamate, neodymium diethylcarbamate, neodymiumdiisopropylcarbamate, neodymium dibutylcarbamate, and neodymiumdibenzylcarbamate.

Suitable neodymium dithiocarbamates include, but are not limited to,neodymium dimethyldithiocarbamate, neodymium diethyldithiocarbamate,neodymium diisopropyldithiocarbamate, neodymium dibutyldithiocarbamate,and neodymium dibenzyldithiocarbamate.

Suitable neodymium xanthates include, but are not limited to, neodymiummethylxanthate, neodymium ethylxanthate, neodymium isopropylxanthate,neodymium butylxanthate, and neodymium benzylxanthate.

Suitable neodymium β-diketonates include, but are not limited to,neodymium acetylacetonate, neodymium trifluoroacetylacetonate, neodymiumhexafluoroacetylacetonate, neodymium benzoylacetonate, and neodymium2,2,6,6-tetramethyl-3,5-heptanedionate.

Suitable neodymium alkoxides or aryloxides include, but are not limitedto, neodymium methoxide, neodymium ethoxide, neodymium isopropoxide,neodymium 2-ethylhexoxide, neodymium phenoxide, neodymiumnonylphenoxide, and neodymium naphthoxide.

Suitable neodymium halides include, but are not limited to, neodymiumfluoride, neodymium chloride, neodymium bromide, and neodymium iodide.Suitable neodymium pseudo-halides include, but are not limited to,neodymium cyanide, neodymium cyanate, neodymium thiocyanate, neodymiumazide, and neodymium ferrocyanide. Suitable neodymium oxyhalidesinclude, but are not limited to, neodymium oxyfluoride, neodymiumoxychloride, and neodymium oxybromide. A Lewis base, such astetrahydrofuran (“THF”), may be employed as an aid for solubilizing thisclass of neodymium compounds in inert organic solvents. Where lanthanidehalides, lanthanide oxyhalides, or other lanthanide-containing compoundscontaining a halogen atom are employed, the lanthanide-containingcompound may also serve as all or part of the halogen source in theabove-mentioned catalyst system.

As used herein, the term organolanthanide compound refers to anylanthanide-containing compound containing at least one lanthanide-carbonbond. These compounds are predominantly, though not exclusively, thosecontaining cyclopentadienyl (“Cp”), substituted cyclopentadienyl, allyl,and substituted allyl ligands. Suitable organolanthanide compoundsinclude, but are not limited to, Cp₃Ln, Cp₂LnR, Cp₂LnCl, CpLnCl₂,CpLn(cyclooctatetraene), (C₅Me₅)₂LnR, LnR₃, Ln(allyl)₃, andLn(allyl)₂Cl, where Ln represents a lanthanide atom, and R represents ahydrocarbyl group. In one or more embodiments, hydrocarbyl groups usefulin the present invention may contain heteroatoms such as, for example,nitrogen, oxygen, boron, silicon, sulfur, and phosphorus atoms.

As mentioned above, the lanthanide-based catalyst systems employed inthe present invention can include an alkylating agent. In one or moreembodiments, alkylating agents, which may also be referred to ashydrocarbylating agents, include organometallic compounds that cantransfer one or more hydrocarbyl groups to another metal. Typically,these agents include organometallic compounds of electropositive metalssuch as Groups 1, 2, and 3 metals (Groups IA, IIA, and IIIA metals).Alkylating agents useful in the present invention include, but are notlimited to, organoaluminum and organomagnesium compounds. As usedherein, the term organoaluminum compound refers to any aluminum compoundcontaining at least one aluminum-carbon bond. In one or moreembodiments, organoaluminum compounds that are soluble in a hydrocarbonsolvent can be employed. As used herein, the term organomagnesiumcompound refers to any magnesium compound that contains at least onemagnesium-carbon bond. In one or more embodiments, organomagnesiumcompounds that are soluble in a hydrocarbon can be employed. As will bedescribed in more detail below, several species of suitable alkylatingagents can be in the form of a halide. Where the alkylating agentincludes a halogen atom, the alkylating agent may also serve as all orpart of the halogen source in the above-mentioned catalyst system.

In one or more embodiments, organoaluminum compounds that can beutilized include those represented by the general formulaAlR_(n)X_(3-n), where each R independently can be a monovalent organicgroup that is attached to the aluminum atom via a carbon atom, whereeach X independently can be a hydrogen atom, a halogen atom, acarboxylate group, an alkoxide group, or an aryloxide group, and where ncan be an integer in the range of from 1 to 3. In one or moreembodiments, each R independently can be a hydrocarbyl group such as,for example, alkyl, cycloalkyl, substituted cycloalkyl, alkenyl,cycloalkenyl, substituted cycloalkenyl, aryl, substituted aryl, aralkyl,alkaryl, allyl, and alkynyl groups, with each group containing in therange of from 1 carbon atom, or the appropriate minimum number of carbonatoms to form the group, up to about 20 carbon atoms. These hydrocarbylgroups may contain heteroatoms including, but not limited to, nitrogen,oxygen, boron, silicon, sulfur, and phosphorus atoms.

Types of the organoaluminum compounds that are represented by thegeneral formula AlR_(n)X_(3-n) include, but are not limited to,trihydrocarbylaluminum, dihydrocarbylaluminum hydride,hydrocarbylaluminum dihydride, dihydrocarbylaluminum carboxylate,hydrocarbylaluminum bis(carboxylate), dihydrocarbylaluminum alkoxide,hydrocarbylaluminum dialkoxide, dihydrocarbylaluminum halide,hydrocarbylaluminum dihalide, dihydrocarbylaluminum aryloxide, andhydrocarbylaluminum diaryloxide compounds. In one embodiment, thealkylating agent can comprise trihydrocarbylaluminum,dihydrocarbylaluminum hydride, and/or hydrocarbylaluminum dihydridecompounds. In one embodiment, when the alkylating agent includes anorganoaluminum hydride compound, the above-mentioned halogen source canbe provided by a tin halide, as disclosed in U.S. Pat. No. 7,008,899,which is incorporated herein by reference in its entirety.

Suitable trihydrocarbylaluminum compounds include, but are not limitedto, trimethylaluminum, triethylaluminum, triisobutylaluminum,tri-n-propylaluminum, triisopropylaluminum, tri-n-butylaluminum,tri-t-butylaluminum, tri-n-pentylaluminum, trineopentylaluminum,tri-n-hexylaluminum, tri-n-octylaluminum, tris(2-ethylhexyl)aluminum,tricyclohexylaluminum, tris(1-methylcyclopentyl)aluminum,triphenylaluminum, tri-p-tolylaluminum,tris(2,6-dimethylphenyl)aluminum, tribenzylaluminum,diethylphenylaluminum, diethyl-p-tolylaluminum, diethylbenzylaluminum,ethyldiphenylaluminum, ethyldi-p-tolylaluminum, andethyldibenzylaluminum.

Suitable dihydrocarbylaluminum hydride compounds include, but are notlimited to, diethylaluminum hydride, di-n-propylaluminum hydride,diisopropylaluminum hydride, di-n-butylaluminum hydride,diisobutylaluminum hydride, di-n-octylaluminum hydride, diphenylaluminumhydride, di-p-tolylaluminum hydride, dibenzylaluminum hydride,phenylethylaluminum hydride, phenyl-n-propylaluminum hydride,phenylisopropylaluminum hydride, phenyl-n-butylaluminum hydride,phenylisobutylaluminum hydride, phenyl-n-octylaluminum hydride,p-tolylethylaluminum hydride, p-tolyl-n-propylaluminum hydride,p-tolylisopropylaluminum hydride, p-tolyl-n-butylaluminum hydride,p-tolylisobutylaluminum hydride, p-tolyl-n-octylaluminum hydride,benzylethylaluminum hydride, benzyl-n-propylaluminum hydride,benzylisopropylaluminum hydride, benzyl-n-butylaluminum hydride,benzylisobutylaluminum hydride, and benzyl-n-octylaluminum hydride.

Suitable hydrocarbylaluminum dihydrides include, but are not limited to,ethylaluminum dihydride, n-propylaluminum dihydride, isopropylaluminumdihydride, n-butylaluminum dihydride, isobutylaluminum dihydride, andn-octylaluminum dihydride.

Suitable dihydrocarbylaluminum halide compounds include, but are notlimited to, diethylaluminum chloride, di-n-propylaluminum chloride,diisopropylaluminum chloride, di-n-butylaluminum chloride,diisobutylaluminum chloride, di-n-octylaluminum chloride,diphenylaluminum chloride, di-p-tolylaluminum chloride, dibenzylaluminumchloride, phenylethylaluminum chloride, phenyl-n-propylaluminumchloride, phenylisopropylaluminum chloride, phenyl-n-butylaluminumchloride, phenylisobutylaluminum chloride, phenyl-n-octylaluminumchloride, p-tolylethylaluminum chloride, p-tolyl-n-propylaluminumchloride, p-tolylisopropylaluminum chloride, p-tolyl-n-butylaluminumchloride, p-tolylisobutylaluminum chloride, p-tolyl-n-octylaluminumchloride, benzylethylaluminum chloride, benzyl-n-propylaluminumchloride, benzylisopropylaluminum chloride, benzyl-n-butylaluminumchloride, benzylisobutylaluminum chloride, and benzyl-n-octylaluminumchloride.

Suitable hydrocarbylaluminum dihalide compounds include, but are notlimited to, ethylaluminum dichloride, n-propylaluminum dichloride,isopropylaluminum dichloride, n-butylaluminum dichloride,isobutylaluminum dichloride, and n-octylaluminum dichloride.

Other organoaluminum compounds useful as alkylating agents that may berepresented by the general formula AlR_(n)X_(3-n) include, but are notlimited to, dimethylaluminum hexanoate, diethylaluminum octoate,diisobutylaluminum 2-ethylhexanoate, dimethylaluminum neodecanoate,diethylaluminum stearate, diisobutylaluminum oleate, methylaluminumbis(hexanoate), ethylaluminum bis(octoate), isobutylaluminumbis(2-ethylhexanoate), methylaluminum bis(neodecanoate), ethylaluminumbis(stearate), isobutylaluminum bis(oleate), dimethylaluminum methoxide,diethylaluminum methoxide, diisobutylaluminum methoxide,dimethylaluminum ethoxide, diethylaluminum ethoxide, diisobutylaluminumethoxide, dimethylaluminum phenoxide, diethylaluminum phenoxide,diisobutylaluminum phenoxide, methylaluminum dimethoxide, ethylaluminumdimethoxide, isobutylaluminum dimethoxide, methylaluminum diethoxide,ethylaluminum diethoxide, isobutylaluminum diethoxide, methylaluminumdiphenoxide, ethylaluminum diphenoxide, and isobutylaluminumdiphenoxide.

Another class of organoaluminum compounds suitable for use as analkylating agent in the present invention is aluminoxanes. Aluminoxanescan comprise oligomeric linear aluminoxanes, which can be represented bythe general formula:

and oligomeric cyclic aluminoxanes, which can be represented by thegeneral formula:

where x can be an integer in the range of from 1 to about 100, or about10 to about 50; y can be an integer in the range of from 2 to about 100,or about 3 to about 20; and where each R independently can be amonovalent organic group that is attached to the aluminum atom via acarbon atom. In one embodiment, each R independently can be ahydrocarbyl group including, but not limited to, alkyl, cycloalkyl,substituted cycloalkyl, alkenyl, cycloalkenyl, substituted cycloalkenyl,aryl, substituted aryl, aralkyl, alkaryl, allyl, and alkynyl groups,with each group containing in the range of from 1 carbon atom, or theappropriate minimum number of carbon atoms to form the group, up toabout 20 carbon atoms. These hydrocarbyl groups may also containheteroatoms including, but not limited to, nitrogen, oxygen, boron,silicon, sulfur, and phosphorus atoms. It should be noted that thenumber of moles of the aluminoxane as used in this application refers tothe number of moles of the aluminum atoms rather than the number ofmoles of the oligomeric aluminoxane molecules. This convention iscommonly employed in the art of catalyst systems utilizing aluminoxanes.

Aluminoxanes can be prepared by reacting trihydrocarbylaluminumcompounds with water. This reaction can be performed according to knownmethods, such as, for example, (1) a method in which thetrihydrocarbylaluminum compound is dissolved in an organic solvent andthen contacted with water, (2) a method in which thetrihydrocarbylaluminum compound is reacted with water of crystallizationcontained in, for example, metal salts, or water adsorbed in inorganicor organic compounds, or (3) a method in which thetrihydrocarbylaluminum compound is reacted with water in the presence ofthe monomer or monomer solution that is to be polymerized.

Suitable aluminoxane compounds include, but are not limited to,methylaluminoxane (“MAO”), modified methylaluminoxane (“MMAO”),ethylaluminoxane, n-propylaluminoxane, isopropylaluminoxane,butylaluminoxane, isobutylaluminoxane, n-pentylaluminoxane,neopentylaluminoxane, n-hexylaluminoxane, n-octylaluminoxane,2-ethylhexylaluminoxane, cyclohexylaluminoxane,1-methylcyclopentylaluminoxane, phenylaluminoxane, and2,6-dimethylphenylaluminoxane. Modified methylaluminoxane can be formedby substituting about 20 to 80 percent of the methyl groups ofmethylaluminoxane with C₂ to C₁₂ hydrocarbyl groups, preferably withisobutyl groups, by using techniques known to those skilled in the art.

Aluminoxanes can be used alone or in combination with otherorganoaluminum compounds. In one embodiment, methylaluminoxane and atleast one other organoaluminum compound (e.g., AlR_(n)X_(3-n)), such asdiisobutyl aluminum hydride, can be employed in combination. U.S.Publication No. 2008/0182954, which is incorporated herein by referencein its entirety, provides other examples where aluminoxanes andorganoaluminum compounds can be employed in combination.

As mentioned above, alkylating agents useful in the present inventioncan comprise organomagnesium compounds. In one or more embodiments,organomagnesium compounds that can be utilized include those representedby the general formula MgR₂, where each R independently can be amonovalent organic group that is attached to the magnesium atom via acarbon atom. In one or more embodiments, each R independently can be ahydrocarbyl group including, but not limited to, alkyl, cycloalkyl,substituted cycloalkyl, alkenyl, cycloalkenyl, substituted cycloalkenyl,aryl, allyl, substituted aryl, aralkyl, alkaryl, and alkynyl groups,with each group containing in the range of from 1 carbon atom, or theappropriate minimum number of carbon atoms to form the group, up toabout 20 carbon atoms. These hydrocarbyl groups may also containheteroatoms including, but not limited to, nitrogen, oxygen, silicon,sulfur, and phosphorus atoms.

Suitable organomagnesium compounds that may be represented by thegeneral formula MgR₂ include, but are not limited to, diethylmagnesium,di-n-propylmagnesium, diisopropylmagnesium, dibutylmagnesium,dihexylmagnesium, diphenylmagnesium, and dibenzylmagnesium.

Another class of organomagnesium compounds that can be utilized as analkylating agent may be represented by the general formula RMgX, where Rcan be a monovalent organic group that is attached to the magnesium atomvia a carbon atom, and X can be a hydrogen atom, a halogen atom, acarboxylate group, an alkoxide group, or an aryloxide group. Where thealkylating agent is an organomagnesium compound that includes a halogenatom, the organomagnesium compound can serve as both the alkylatingagent and at least a portion of the halogen source in the catalystsystems. In one or more embodiments, R can be a hydrocarbyl groupincluding, but not limited to, alkyl, cycloalkyl, substitutedcycloalkyl, alkenyl, cycloalkenyl, substituted cycloalkenyl, aryl,allyl, substituted aryl, aralkyl, alkaryl, and alkynyl groups, with eachgroup containing in the range of from 1 carbon atom, or the appropriateminimum number of carbon atoms to form the group, up to about 20 carbonatoms. These hydrocarbyl groups may also contain heteroatoms including,but not limited to, nitrogen, oxygen, boron, silicon, sulfur, andphosphorus atoms. In one embodiment, X can be a carboxylate group, analkoxide group, or an aryloxide group, with each group containing in therange of from 1 to about 20 carbon atoms.

Types of organomagnesium compounds that may be represented by thegeneral formula RMgX include, but are not limited to,hydrocarbylmagnesium hydride, hydrocarbylmagnesium halide,hydrocarbylmagnesium carboxylate, hydrocarbylmagnesium alkoxide, andhydrocarbylmagnesium aryloxide.

Suitable organomagnesium compounds that may be represented by thegeneral formula RMgX include, but are not limited to, methylmagnesiumhydride, ethylmagnesium hydride, butylmagnesium hydride, hexylmagnesiumhydride, phenylmagnesium hydride, benzylmagnesium hydride,methylmagnesium chloride, ethylmagnesium chloride, butylmagnesiumchloride, hexylmagnesium chloride, phenylmagnesium chloride,benzylmagnesium chloride, methylmagnesium bromide, ethylmagnesiumbromide, butylmagnesium bromide, hexylmagnesium bromide, phenylmagnesiumbromide, benzylmagnesium bromide, methylmagnesium hexanoate,ethylmagnesium hexanoate, butylmagnesium hexanoate, hexylmagnesiumhexanoate, phenylmagnesium hexanoate, benzylmagnesium hexanoate,methylmagnesium ethoxide, ethylmagnesium ethoxide, butylmagnesiumethoxide, hexylmagnesium ethoxide, phenylmagnesium ethoxide,benzylmagnesium ethoxide, methylmagnesium phenoxide, ethylmagnesiumphenoxide, butylmagnesium phenoxide, hexylmagnesium phenoxide,phenylmagnesium phenoxide, and benzylmagnesium phenoxide.

As mentioned above, the lanthanide-based catalyst systems employed inthe present invention can include a halogen source. As used herein, theterm halogen source refers to any substance including at least onehalogen atom. In one or more embodiments, at least a portion of thehalogen source can be provided by either of the above-describedlanthanide-containing compound and/or the above-described alkylatingagent, when those compounds contain at least one halogen atom. In otherwords, the lanthanide-containing compound can serve as both thelanthanide-containing compound and at least a portion of the halogensource. Similarly, the alkylating agent can serve as both the alkylatingagent and at least a portion of the halogen source.

In another embodiment, at least a portion of the halogen source can bepresent in the catalyst systems in the form of a separate and distincthalogen-containing compound. Various compounds, or mixtures thereof,that contain one or more halogen atoms can be employed as the halogensource. Examples of halogen atoms include, but are not limited to,fluorine, chlorine, bromine, and iodine. A combination of two or morehalogen atoms can also be utilized. Halogen-containing compounds thatare soluble in a hydrocarbon solvent are suitable for use in the presentinvention. Hydrocarbon-insoluble halogen-containing compounds, however,can be suspended in a polymerization system to form the catalyticallyactive species, and are therefore also useful.

Useful types of halogen-containing compounds that can be employedinclude, but are not limited to, elemental halogens, mixed halogens,hydrogen halides, organic halides, inorganic halides, metallic halides,and organometallic halides.

Elemental halogens suitable for use in the present invention include,but are not limited to, fluorine, chlorine, bromine, and iodine. Somespecific examples of suitable mixed halogens include iodinemonochloride, iodine monobromide, iodine trichloride, and iodinepentafluoride.

Hydrogen halides include, but are not limited to, hydrogen fluoride,hydrogen chloride, hydrogen bromide, and hydrogen iodide.

Organic halides include, but are not limited to, t-butyl chloride,t-butyl bromide, allyl chloride, allyl bromide, benzyl chloride, benzylbromide, chloro-di-phenylmethane, bromo-di-phenylmethane,triphenylmethyl chloride, triphenylmethyl bromide, benzylidene chloride,benzylidene bromide, methyltrichlorosilane, phenyltrichlorosilane,dimethyldichlorosilane, diphenyldichlorosilane, trimethylchlorosilane,benzoyl chloride, benzoyl bromide, propionyl chloride, propionylbromide, methyl chloroformate, and methyl bromoformate.

Inorganic halides include, but are not limited to, phosphorustrichloride, phosphorus tribromide, phosphorus pentachloride, phosphorusoxychloride, phosphorus oxybromide, boron trifluoride, borontrichloride, boron tribromide, silicon tetrafluoride, silicontetrachloride, silicon tetrabromide, silicon tetraiodide, arsenictrichloride, arsenic tribromide, arsenic triiodide, seleniumtetrachloride, selenium tetrabromide, tellurium tetrachloride, telluriumtetrabromide, and tellurium tetraiodide.

Metallic halides include, but are not limited to, tin tetrachloride, tintetrabromide, aluminum trichloride, aluminum tribromide, antimonytrichloride, antimony pentachloride, antimony tribromide, aluminumtriiodide, aluminum trifluoride, gallium trichloride, galliumtribromide, gallium triiodide, gallium trifluoride, indium trichloride,indium tribromide, indium triiodide, indium trifluoride, titaniumtetrachloride, titanium tetrabromide, titanium tetraiodide, zincdichloride, zinc dibromide, zinc diiodide, and zinc difluoride.

Organometallic halides include, but are not limited to, dimethylaluminumchloride, diethylaluminum chloride, dimethylaluminum bromide,diethylaluminum bromide, dimethylaluminum fluoride, diethylaluminumfluoride, methylaluminum dichloride, ethylaluminum dichloride,methylaluminum dibromide, ethylaluminum dibromide, methylaluminumdifluoride, ethylaluminum difluoride, methylaluminum sesquichloride,ethylaluminum sesquichloride, isobutylaluminum sesquichloride,methylmagnesium chloride, methylmagnesium bromide, methylmagnesiumiodide, ethylmagnesium chloride, ethylmagnesium bromide, butylmagnesiumchloride, butylmagnesium bromide, phenylmagnesium chloride,phenylmagnesium bromide, benzylmagnesium chloride, trimethyltinchloride, trimethyltin bromide, triethyltin chloride, triethyltinbromide, di-t-butyltin dichloride, di-t-butyltin dibromide, dibutyltindichloride, dibutyltin dibromide, tributyltin chloride, and tributyltinbromide.

In one or more embodiments, the above-described catalyst systems cancomprise a compound containing a non-coordinating anion or anon-coordinating anion precursor. In one or more embodiments, a compoundcontaining a non-coordinating anion, or a non-coordinating anionprecursor can be employed in lieu of the above-described halogen source.A non-coordinating anion is a sterically bulky anion that does not formcoordinate bonds with, for example, the active center of a catalystsystem due to steric hindrance. Non-coordinating anions useful in thepresent invention include, but are not limited to, tetraarylborateanions and fluorinated tetraarylborate anions. Compounds containing anon-coordinating anion can also contain a counter cation, such as acarbonium, ammonium, or phosphonium cation. Exemplary counter cationsinclude, but are not limited to, triarylcarbonium cations andN,N-dialkylanilinium cations. Examples of compounds containing anon-coordinating anion and a counter cation include, but are not limitedto, triphenylcarbonium tetrakis (pentafluorophenyl)borate,N,N-dimethylanilinium tetrakis (pentafluorophenyl)borate,triphenylcarbonium tetrakis [3,5-bis(trifluoromethyl)phenyl]borate, andN,N-dimethylanilinium tetrakis [3,5-bis(trifluoromethyl)phenyl]borate.

A non-coordinating anion precursor can also be used in this embodiment.A non-coordinating anion precursor is a compound that is able to form anon-coordinating anion under reaction conditions. Usefulnon-coordinating anion precursors include, but are not limited to,triarylboron compounds, BR₃, where R is a strong electron-withdrawingaryl group, such as a pentafluorophenyl or3,5-bis(trifluoromethyl)phenyl group.

The lanthanide-based catalyst composition used in this invention may beformed by combining or mixing the foregoing catalyst ingredients.Although one or more active catalyst species are believed to result fromthe combination of the lanthanide-based catalyst ingredients, the degreeof interaction or reaction between the various catalyst ingredients orcomponents is not known with any great degree of certainty. Therefore,the term “catalyst composition” has been employed to encompass a simplemixture of the ingredients, a complex of the various ingredients that iscaused by physical or chemical forces of attraction, a chemical reactionproduct of the ingredients, or a combination of the foregoing.

The foregoing lanthanide-based catalyst composition may have highcatalytic activity for polymerizing conjugated dienes intocis-1,4-polydienes over a wide range of catalyst concentrations andcatalyst ingredient ratios. Several factors may impact the optimumconcentration of any one of the catalyst ingredients. For example,because the catalyst ingredients may interact to form an active species,the optimum concentration for any one catalyst ingredient may bedependent upon the concentrations of the other catalyst ingredients.

In one or more embodiments, the molar ratio of the alkylating agent tothe lanthanide-containing compound (alkylating agent/Ln) can be variedfrom about 1:1 to about 1,000:1, in other embodiments from about 2:1 toabout 500:1, and in other embodiments from about 5:1 to about 200:1.

In those embodiments where both an aluminoxane and at least one otherorganoaluminum agent are employed as alkylating agents, the molar ratioof the aluminoxane to the lanthanide-containing compound(aluminoxane/Ln) can be varied from 5:1 to about 1,000:1, in otherembodiments from about 10:1 to about 700:1, and in other embodimentsfrom about 20:1 to about 500:1; and the molar ratio of the at least oneother organoaluminum compound to the lanthanide-containing compound(Al/Ln) can be varied from about 1:1 to about 200:1, in otherembodiments from about 2:1 to about 150:1, and in other embodiments fromabout 5:1 to about 100:1.

The molar ratio of the halogen-containing compound to thelanthanide-containing compound is best described in terms of the ratioof the moles of halogen atoms in the halogen source to the moles oflanthanide atoms in the lanthanide-containing compound (halogen/Ln). Inone or more embodiments, the halogen/Ln molar ratio can be varied fromabout 0.5:1 to about 20:1, in other embodiments from about 1:1 to about10:1, and in other embodiments from about 2:1 to about 6:1.

In yet another embodiment, the molar ratio of the non-coordinating anionor non-coordinating anion precursor to the lanthanide-containingcompound (An/Ln) may be from about 0.5:1 to about 20:1, in otherembodiments from about 0.75:1 to about 10:1, and in other embodimentsfrom about 1:1 to about 6:1.

The lanthanide-based catalyst composition can be formed by variousmethods.

In one embodiment, the lanthanide-based catalyst composition may beformed in situ by adding the catalyst ingredients to a solutioncontaining monomer and solvent, or to bulk monomer, in either a stepwiseor simultaneous manner. In one embodiment, the alkylating agent can beadded first, followed by the lanthanide-containing compound, and thenfollowed by the halogen source or by the compound containing anon-coordinating anion or the non-coordinating anion precursor.

In another embodiment, the lanthanide-based catalyst composition may bepreformed. That is, the catalyst ingredients are pre-mixed outside thepolymerization system either in the absence of any monomer or in thepresence of a small amount of at least one conjugated diene monomer atan appropriate temperature, which may be from about −20° C. to about 80°C. The amount of conjugated diene monomer that may be used forpreforming the catalyst can range from about 1 to about 500 moles, inother embodiments from about 5 to about 250 moles, and in otherembodiments from about 10 to about 100 moles per mole of thelanthanide-containing compound. The resulting catalyst composition maybe aged, if desired, prior to being added to the monomer that is to bepolymerized.

In yet another embodiment, the lanthanide-based catalyst composition maybe formed by using a two-stage procedure. The first stage may involvecombining the alkylating agent with the lanthanide-containing compoundeither in the absence of any monomer or in the presence of a smallamount of at least one conjugated diene monomer at an appropriatetemperature, which may be from about −20° C. to about 80° C. The amountof monomer employed in the first stage may be similar to that set forthabove for performing the catalyst. In the second stage, the mixtureformed in the first stage and the halogen source, non-coordinatinganion, or non-coordinating anion precursor can be charged in either astepwise or simultaneous manner to the monomer that is to bepolymerized.

In one or more embodiments, the reactive polymer is prepared by anionicpolymerization, wherein monomer is polymerized by using an anionicinitiator. The key mechanistic features of anionic polymerization havebeen described in books (e.g., Hsieh, H. L.; Quirk, R. P. AnionicPolymerization: Principles and Practical Applications; Marcel Dekker:New York, 1996) and review articles (e.g., Hadjichristidis, N.;Pitsikalis, M.; Pispas, S.; Iatrou, H.; Chem. Rev. 2001, 101(12),3747-3792). Anionic initiators may advantageously produce livingpolymers that, prior to quenching, are capable of reacting withadditional monomers for further chain growth or reacting with certainfunctionalizing agents to give functionalized polymers.

The practice of this invention is not limited by the selection of anyparticular anionic initiators. In one or more embodiments, the anionicinitiator employed is a functional initiator that imparts a functionalgroup at the head of the polymer chain (i.e., the location from whichthe polymer chain is started). In particular embodiments, the functionalgroup includes one or more heteroatoms (e.g., nitrogen, oxygen, boron,silicon, sulfur, tin, and phosphorus atoms) or heterocyclic groups. Incertain embodiments, the functional group reduces the 50° C. hysteresisloss of carbon-black filled vulcanizates prepared from polymerscontaining the functional group as compared to similar carbon-blackfilled vulcanizates prepared from polymer that does not include thefunctional group.

Exemplary anionic initiators include organolithium compounds. In one ormore embodiments, organolithium compounds may include heteroatoms. Inthese or other embodiments, organolithium compounds may include one ormore heterocyclic groups.

Types of organolithium compounds include alkyllithium, aryllithiumcompounds, and cycloalkyllithium compounds. Specific examples oforganolithium compounds include ethyllithium, n-propyllithium,isopropyllithium, n-butyllithium, sec-butyllithium, t-butyllithium,n-amyllithium, isoamyllithium, and phenyllithium. Other examples includealkylmagnesium halide compounds such as butylmagnesium bromide andphenylmagnesium bromide. Still other anionic initiators includeorganosodium compounds such as phenylsodium and2,4,6-trimethylphenylsodium. Also contemplated are those anionicinitiators that give rise to di-living polymers, wherein both ends of apolymer chain are living. Examples of such initiators include dilithioinitiators such as those prepared by reacting 1,3-diisopropenylbenzenewith sec-butyllithium. These and related difunctional initiators aredisclosed in U.S. Pat. No. 3,652,516, which is incorporated herein byreference. Radical anionic initiators may also be employed, includingthose described in U.S. Pat. No. 5,552,483, which is incorporated hereinby reference.

In particular embodiments, the organolithium compounds include a cyclicamine-containing compound such as lithiohexamethyleneimine. These andrelated useful initiators are disclosed in the U.S. Pat. Nos. 5,332,810,5,329,005, 5,578,542, 5,393,721, 5,698,646, 5,491,230, 5,521,309,5,496,940, 5,574,109, and 5,786,441, which are incorporated herein byreference. In other embodiments, the organolithium compounds includelithiated alkylthioacetals such as 2-lithio-2-methyl-1,3-dithiane. Theseand related useful initiators are disclosed in U.S. Publ. Nos.2006/0030657, 2006/0264590, and 2006/0264589, which are incorporatedherein by reference. In still other embodiments, the organolithiumcompounds include alkoxysilyl-containing initiators, such as lithiatedt-butyldimethylpropoxysilane. These and related useful initiators aredisclosed in U.S. Publ. No. 2006/0241241, which is incorporated hereinby reference.

In one or more embodiments, the anionic initiator employed istrialkyltinlithium compound such as tri-n-butyltinlithium. These andrelated useful initiators are disclosed in U.S. Pat. Nos. 3,426,006 and5,268,439, which are incorporated herein by reference.

When elastomeric copolymers containing conjugated diene monomers andvinyl-substituted aromatic monomers are prepared by anionicpolymerization, the conjugated diene monomers and vinyl-substitutedaromatic monomers may be used at a weight ratio of 95:5 to 50:50, or inother embodiments, 90:10 to 65:35. In order to promote the randomizationof comonomers in copolymerization and to control the microstructure(such as 1,2-linkage of conjugated diene monomer) of the polymer, arandomizer, which is typically a polar coordinator, may be employedalong with the anionic initiator.

Compounds useful as randomizers include those having an oxygen ornitrogen heteroatom and a non-bonded pair of electrons. Exemplary typesof randomizers include linear and cyclic oligomeric oxolanyl alkanes;dialkyl ethers of mono and oligo alkylene glycols (also known as glymeethers); crown ethers; tertiary amines; linear THF oligomers; alkalimetal alkoxides; and alkali metal sulfonates. Linear and cyclicoligomeric oxolanyl alkanes are described in U.S. Pat. No. 4,429,091,which is incorporated herein by reference. Specific examples ofrandomizers include 2,2-bis(2′-tetrahydrofuryl)propane,1,2-dimethoxyethane, N,N,N′,N′-tetramethylethylenediamine (TMEDA),tetrahydrofuran (THF), 1,2-dipiperidylethane, dipiperidylmethane,hexamethylphosphoramide, N,N′-dimethylpiperazine, diazabicyclooctane,dimethyl ether, diethyl ether, tri-n-butylamine, potassium t-amylate,potassium 4-dodecylsulfonate, and mixtures thereof.

The amount of randomizer to be employed may depend on various factorssuch as the desired microstructure of the polymer, the ratio of monomerto comonomer, the polymerization temperature, as well as the nature ofthe specific randomizer employed. In one or more embodiments, the amountof randomizer employed may range between 0.05 and 100 moles per mole ofthe anionic initiator.

The anionic initiator and the randomizer can be introduced to thepolymerization system by various methods. In one or more embodiments,the anionic initiator and the randomizer may be added separately to themonomer to be polymerized in either a stepwise or simultaneous manner.In other embodiments, the anionic initiator and the randomizer may bepre-mixed outside the polymerization system either in the absence of anymonomer or in the presence of a small amount of monomer, and theresulting mixture may be aged, if desired, and then added to the monomerthat is to be polymerized.

In one or more embodiments, regardless of whether a coordinationcatalyst or an anionic initiator is used to prepare the reactivepolymer, a solvent may be employed as a carrier to either dissolve orsuspend the catalyst or initiator in order to facilitate the delivery ofthe catalyst or initiator to the polymerization system. In otherembodiments, monomer can be used as the carrier. In yet otherembodiments, the catalyst or initiator can be used in their neat statewithout any solvent.

In one or more embodiments, suitable solvents include those organiccompounds that will not undergo polymerization or incorporation intopropagating polymer chains during the polymerization of monomer in thepresence of the catalyst or initiator. In one or more embodiments, theseorganic species are liquid at ambient temperature and pressure. In oneor more embodiments, these organic solvents are inert to the catalyst orinitiator. Exemplary organic solvents include hydrocarbons with a low orrelatively low boiling point such as aromatic hydrocarbons, aliphatichydrocarbons, and cycloaliphatic hydrocarbons. Non-limiting examples ofaromatic hydrocarbons include benzene, toluene, xylenes, ethylbenzene,diethylbenzene, and mesitylene. Non-limiting examples of aliphatichydrocarbons include n-pentane, n-hexane, n-heptane, n-octane, n-nonane,n-decane, isopentane, isohexanes, isopentanes, isooctanes,2,2-dimethylbutane, petroleum ether, kerosene, and petroleum spirits.And, non-limiting examples of cycloaliphatic hydrocarbons includecyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane.Mixtures of the above hydrocarbons may also be used. As is known in theart, aliphatic and cycloaliphatic hydrocarbons may be desirably employedfor environmental reasons. The low-boiling hydrocarbon solvents aretypically separated from the polymer upon completion of thepolymerization.

Other examples of organic solvents include high-boiling hydrocarbons ofhigh molecular weights, including hydrocarbon oils that are commonlyused to oil-extend polymers. Examples of these oils include paraffinicoils, aromatic oils, naphthenic oils, vegetable oils other than castoroils, and low PCA oils including MES, TDAE, SRAE, heavy naphthenic oils.Since these hydrocarbons are non-volatile, they typically do not requireseparation and remain incorporated in the polymer.

The production of the reactive polymer according to this invention canbe accomplished by polymerizing conjugated diene monomer, optionallytogether with monomer copolymerizable with conjugated diene monomer, inthe presence of a catalytically effective amount of the catalyst orinitiator. The introduction of the catalyst or initiator, the conjugateddiene monomer, optionally the comonomer, and any solvent, if employed,forms a polymerization mixture in which the reactive polymer is formed.The amount of the catalyst or initiator to be employed may depend on theinterplay of various factors such as the type of catalyst or initiatoremployed, the purity of the ingredients, the polymerization temperature,the polymerization rate and conversion desired, the molecular weightdesired, and many other factors. Accordingly, a specific catalyst orinitiator amount cannot be definitively set forth except to say thatcatalytically effective amounts of the catalyst or initiator may beused.

In one or more embodiments, the amount of the coordinating metalcompound (e.g., a lanthanide-containing compound) used can be variedfrom about 0.001 to about 2 mmol, in other embodiments from about 0.005to about 1 mmol, and in still other embodiments from about 0.01 to about0.2 mmol per 100 gram of monomer.

In other embodiments, where an anionic initiator (e.g., an alkyllithiumcompound) is employed, the initiator loading may be varied from about0.05 to about 100 mmol, in other embodiments from about 0.1 to about 50mmol, and in still other embodiments from about 0.2 to about 5 mmol per100 gram of monomer.

In one or more embodiments, the polymerization may be carried out in apolymerization system that includes a substantial amount of solvent. Inone embodiment, a solution polymerization system may be employed inwhich both the monomer to be polymerized and the polymer formed aresoluble in the solvent. In another embodiment, a precipitationpolymerization system may be employed by choosing a solvent in which thepolymer formed is insoluble. In both cases, an amount of solvent inaddition to the amount of solvent that may be used in preparing thecatalyst or initiator is usually added to the polymerization system. Theadditional solvent may be the same as or different from the solvent usedin preparing the catalyst or initiator. Exemplary solvents have been setforth above. In one or more embodiments, the solvent content of thepolymerization mixture may be more than 20% by weight, in otherembodiments more than 50% by weight, and in still other embodiments morethan 80% by weight based on the total weight of the polymerizationmixture.

In other embodiments, the polymerization system employed may begenerally considered a bulk polymerization system that includessubstantially no solvent or a minimal amount of solvent. Those skilledin the art will appreciate the benefits of bulk polymerization processes(i.e., processes where monomer acts as the solvent), and therefore thepolymerization system includes less solvent than will deleteriouslyimpact the benefits sought by conducting bulk polymerization. In one ormore embodiments, the solvent content of the polymerization mixture maybe less than about 20% by weight, in other embodiments less than about10% by weight, and in still other embodiments less than about 5% byweight based on the total weight of the polymerization mixture. Inanother embodiment, the polymerization mixture contains no solventsother than those that are inherent to the raw materials employed. Instill another embodiment, the polymerization mixture is substantiallydevoid of solvent, which refers to the absence of that amount of solventthat would otherwise have an appreciable impact on the polymerizationprocess. Polymerization systems that are substantially devoid of solventmay be referred to as including substantially no solvent. In particularembodiments, the polymerization mixture is devoid of solvent.

The polymerization may be conducted in any conventional polymerizationvessels known in the art. In one or more embodiments, solutionpolymerization can be conducted in a conventional stirred-tank reactor.In other embodiments, bulk polymerization can be conducted in aconventional stirred-tank reactor, especially if the monomer conversionis less than about 60%. In still other embodiments, especially where themonomer conversion in a bulk polymerization process is higher than about60%, which typically results in a highly viscous cement, the bulkpolymerization may be conducted in an elongated reactor in which theviscous cement under polymerization is driven to move by piston, orsubstantially by piston. For example, extruders in which the cement ispushed along by a self-cleaning single-screw or double-screw agitatorare suitable for this purpose. Examples of useful bulk polymerizationprocesses are disclosed in U.S. Pat. No. 7,351,776, which isincorporated herein by reference.

In one or more embodiments, all of the ingredients used for thepolymerization can be combined within a single vessel (e.g., aconventional stirred-tank reactor), and all steps of the polymerizationprocess can be conducted within this vessel. In other embodiments, twoor more of the ingredients can be pre-combined in one vessel and thentransferred to another vessel where the polymerization of monomer (or atleast a major portion thereof) may be conducted.

The polymerization can be carried out as a batch process, a continuousprocess, or a semi-continuous process. In the semi-continuous process,the monomer is intermittently charged as needed to replace that monomeralready polymerized. In one or more embodiments, the conditions underwhich the polymerization proceeds may be controlled to maintain thetemperature of the polymerization mixture within a range from about −10°C. to about 200° C., in other embodiments from about 0° C. to about 150°C., and in other embodiments from about 20° C. to about 100° C. In oneor more embodiments, the heat of polymerization may be removed byexternal cooling by a thermally controlled reactor jacket, internalcooling by evaporation and condensation of the monomer through the useof a reflux condenser connected to the reactor, or a combination of thetwo methods. Also, the polymerization conditions may be controlled toconduct the polymerization under a pressure of from about 0.1 atmosphereto about 50 atmospheres, in other embodiments from about 0.5 atmosphereto about 20 atmosphere, and in other embodiments from about 1 atmosphereto about 10 atmospheres. In one or more embodiments, the pressures atwhich the polymerization may be carried out include those that ensurethat the majority of the monomer is in the liquid phase. In these orother embodiments, the polymerization mixture may be maintained underanaerobic conditions.

Regardless of whether the polymerization is catalyzed or initiated by acoordination catalyst (e.g., a lanthanide-based catalyst) or an anionicinitiator (e.g., an alkyllithium initiator), some or all of theresulting polymer chains may possess reactive chain ends before thepolymerization mixture is quenched. As noted above, the reactive polymerprepared with a coordination catalyst (e.g., a lanthanide-basedcatalyst) may be referred to as a pseudo-living polymer, and thereactive polymer prepared with an anionic initiator (e.g., analkyllithium initiator) may be referred to as a living polymer. In oneor more embodiments, a polymerization mixture including reactive polymermay be referred to as an active polymerization mixture. The percentageof polymer chains possessing a reactive end depends on various factorssuch as the type of catalyst or initiator, the type of monomer, thepurity of the ingredients, the polymerization temperature, the monomerconversion, and many other factors. In one or more embodiments, at leastabout 20% of the polymer chains possess a reactive end, in otherembodiments at least about 50% of the polymer chains possess a reactiveend, and in still other embodiments at least about 80% of the polymerchains possess a reactive end. In any event, the reactive polymer can bereacted with a polycyano compound to form the functionalized polymer ofthis invention.

In one or more embodiments, polycyano compounds include at least twocyano groups, which may be referred to as nitrile groups. In one or moreembodiments, the cyano groups may be defined by the formula —C≡N. In oneor more embodiments, polycyano compounds may be represented by theformula τ-(C≡N), where τ is a polyvalent organic moiety having a valenceof at least two and n is an integer equal to the valence of thepolyvalent organic moiety τ. In particular embodiments, τ is anon-heterocyclic polyvalent organic moiety. In other words, τ is devoidof heterocyclic groups, which may be saturated or unsaturated, may bemonocyclic, bicylcic, tricyclic or multicyclic, and may include one ormore heteroatoms that may be the same or distinct. In one or moreembodiments, τ is an acyclic polyvalent organic moiety (either linear orbranched) that may or may not include one or more heteroatoms. In otherembodiments, τ is a cyclic polyvalent organic moiety that is devoid ofheteroatoms within the ring of the cyclic moiety. Exemplary heteroatomsinclude nitrogen, oxygen, sulfur, boron, silicon, tin, and phosphorous.

In one or more embodiments, polycyano compounds may be represented bythe formula N≡C—R¹—C≡N, where R¹ is a divalent organic group. In one ormore embodiments, divalent organic groups may include hydrocarbylenegroups or substituted hydrocarbylene groups such as, but not limited to,alkylene, cycloalkylene, alkenylene, cycloalkenylene, alkynylene,cycloalkynylene, or arylene groups. Substituted hydrocarbylene groupsinclude hydrocarbylene groups in which one or more hydrogen atoms havebeen replaced by a substituent such as an alkyl group. In one or moreembodiments, these groups may include from one or two, or theappropriate minimum number of carbon atoms to form the group, to about20 carbon atoms. These groups may also contain one or more heteroatoms.In particular embodiments, R¹ is a non-heterocyclic divalent group. Inone or more embodiments, R¹ is an acyclic divalent organic group (eitherlinear or branched) that may or may not include one or more heteroatoms.In other embodiments, R¹ is a cyclic divalent organic group that isdevoid of heteroatoms. In one or more embodiments, R¹ may contain one ormore additional cyano groups (i.e., —C≡N).

Exemplary types of polycyano compounds include (polycyano)arene,(polycyano) alkane, (polycyano) alkene, (polycyano) alkyne, (polycyano)cycloalkane, (polycyano)cycicoalkene, and (polycyano)cycloalkynecompounds. Those skilled in the art appreciate that (polycyano) arenecompounds include arene compounds where at least two hydrogen atoms onthe arene compound have been replaced by cyano groups, and those skilledin the art appreciate that the other classes of polycyano compounds canbe similarly identified.

In one or more embodiments, exemplary types of (polycyano)arenecompounds include dicyanoarene, tricyanoarene, and tetracyanoarenecompounds. Exemplary types of (polycyano)alkane compounds includedicyanoalkane, tricyanoalkane, and tetracyanoalkane compounds. Exemplarytypes of (polycyano)alkene compounds include dicyanoalkene,tricyanoalkene, and tetracyanoalkene compounds. Exemplary types of(polycyano)alkyne compounds include dicyanoalkyne, tricyanoalkyne, andtetracyanoalkyne compounds. Exemplary types of (polycyano)cycloalkanecompounds include dicyanocycloalkane, tricyanocycloalkane, andtetracyanocycloalkane compounds. Exemplary types of(polycyano)cycloalkene compounds include dicyanocycloalkene,tricyanocycloalkene, and tetracyanocycloalkene compounds. Exemplarytypes of (polycyano)cycloalkyne compounds include dicyanocycloalkyne,tricyanocycloalkyne, and tetracyanocycloalkyne compounds.

Specific examples of (polycyano)arene compounds include1,2-dicyanobenzene (phthalonitrile), 1,3-dicyanobenzene(isophthalodinitrile or isophthalonitrile), 1,4-dicyanobenzene(terephthalonitrile), 1,2-dicyanonaphthalene, 1,3-dicyanonaphthalene,1,4-dicyanonaphthalene, 1,5-dicyanonaphthalene, 1,6-dicyanonaphthalene,1,7-dicyanonaphthalene, 1,8-dicyanonaphthalene, 2,3-dicyanonaphthalene,2,4-dicyanonaphthalene, 1,1′-biphenyl)-4,4′-dicarbonitrile,1,2-dicyanoanthracene, 1,3-dicyanoanthracene, 1,4-dicyanoanthracene,1,8-dicyanoanthracene, 1,9-dicyanoanthracene, 2,3-dicyanoanthracene,2,4-dicyanoanthracene, 9,10-dicyanoanthracene, 9,10-dicyanophenanthrene,1,2-dicyanoindene, 1,4-dicyanoindene, 2,6-dicyanoindene,1,2-dicyanoazulene, 1,3-dicyanoazulene, 4,5-dicyanoazulene,1,8-dicyanofluorene, 1,9-dicyanofluorene, 4,5-dicyanofluorene,2,6-dicyanotoluene, 2-cyanophenylacetonitrile,4-cyanophenylacetonitrile, 1,3,5-tricyanobenzene, 1,2,4-tricyanobenzene,1,2,5-tricyanobenzene, 1,4,6-tricyanoindene, 1,3,7-tricyanonaphthalene,1,2,4,5-tetracyanobenezene, and 1,3,5,6-tetracyanonaphthalene.

Specific examples of (polycyano)alkane compounds include malononitrile,1,2-dicyanoethane(succinonitrile), 1,2-dicyano-1,2-diphenylethane,1,3-dicyanopropane(glutaronitrile), 2-methylglutaronitrile,1,2-dicyanopropane, dimethylmalononitrile, diphenylmalononitrile,1,4-dicyanobutane(adiponitrile), 1,5-dicyanopentane(pimelonitrile),1,6-dicyanohexane(suberonitrile), 1,7-dicyanoheptane,1,8-dicyanooctane(sebaconitrile), 3,3′-thiodipropionitrile,1,1,3-tricyanopropane, 1,1,2-tricyanopropane, 1,1,4-tricyanobutane,1,1,5-tricyanopentane, 1,1,6-tricyanohexane, 1,3,5-tricyanohexane,1,2,5-tricyanoheptane, 2,4,6-tricyanooctane, tris(2-cyanoethyl)amine,1,1,3,3-tetracyanopropane, 1,1,4,4-tetracyanobutane,1,1,6,6,-tetracyanohexane, and 1,2,4,5-tetracyanohexane.

Specific examples of (polycyano)alkene compounds include fumaronitrile,1,3-dicyanopropene, cis-1,4-dicyano-2-butene,trans-1,4-dicyano-2-butene, 2-methyleneglutaronitrile,benzylidenemalononitrile, 1,1,2-tricyanoethylene, 1,1,3-tricyanopropene,1,1,4-tricyano-2-butene, 1,1,5-tricyano-2-pentene, tetracyanoethylene,7,8,8-tetracyanoquinodimethane, and 1,1,4,4-tetracyano-2-butene.

Specific examples of (polycyano)alkyne compounds include3,3-dicyanopropyne, 3,4-dicyano-1-butyne, 3,4-dicyano-1-pentyne,3,4-dicyano-1-pentyne, 3,5-dicyano-1-pentyne, 3,4-dicyano-1-hexyne,3,5-dicyano-1-hexyne, 3,6-dicyano-1-hexyne, 4,5-dicyano-1-hexyne,4,6-dicyano-1-hexyne, 5,6-dicyano-1-hexyne, 1,3,3-tricyanopropyne,1,3,4-tricyano-1-butyne, 1,3,4-tricyano-1-pentyne,1,3,4-tricyano-1-pentyne, 1,3,5-tricyano-1-pentyne,1,4,5-tricyano-1-pentyne, 3,4,5-tricyano-1-hexyne,3,4,6-tricyano-1-hexyne, 3,5,6-tricyano-1-hexyne,3,4,5-tricyano-1-hexyne, and 1,1,4,4-tetracyano-2-butyne.

Specific examples of (polycyano)cycloalkane compounds include1,2-dicyanocyclobutane, 1,2-dicyanocyclopentane,1,3-dicyanocyclopentane, 1,2-dicyanocyclohexane, 1,3-dicyanocyclohexane,1,4-dicyanocyclohexane, 1,2-dicyanocycloheptane,1,3-dicyanocycloheptane, 1,4-dicyanocycloheptane,1,2-dicyanocyclooctane, 1,3-dicyanocyclooctane, 1,4-dicyanocyclooctane,1,5-dicyanocyclooctane, 1,2,4-tricyanocyclohexane,1,3,4-tricyanocyclohexane, 1,2,4-tricyanocycloheptane,1,3,4-tricyanocycloheptane, 1,2,4-tricyanocyclooctane,1,2,5-tricyanocyclooctane, 1,3,5-tricyanocyclooctane,1,2,3,4-tetracyanocyclohexane, 2,2,4,4-tetracyclohexane,1,2,3,4-tetracyanocycloheptane, 1,1,4,4-tetracyanocycloheptane,1,2,3,4-tetracyanocyclooctane, 1,2,3,5-tetracyanocyclooctane,3,3-dimethylcyclopropane-1,1,2,2-tetracyanocarbonitrile, and spiro (2.4)heptane-1,1,2,2-tetracarbonitrile.

Specific examples of (polycyano)cycloalkene compounds include1,2-dicyanocyclopentene, 1,3-dicyanocyclopentene,1,4-dicyanocyclopentene, 1,2-dicyanocyclohexene, 1,3-dicyanohexene,1,4-dicyanocyclohexene, 3,6-dicyanocyclohexene, 1,2-dicyanocycloheptene,1,3-dicyanocycloheptene, 1,4-dicyanocycloheptene,1,6-dicyanocyclooctene, 3,4-dicyanocycloheptene,1,2,3-tricyanocyclopentene, 1,2,4-tricyanocyclopentene,1,2,4-tricyanocyclohexene, 1,3,5-tricyanocyclohexene,1,2,4-tricyanocycloheptene, 1,3,4-tricyanocycloheptene,1,2,3-tricyanocyclooctene, 1,2,5-tricyanocyclooctene,1,2,3,4-tetracyanocyclohexene, 3,3,4,4-tetracyanocyclohexene,1,2,4,5-tetracyanocycloheptene, 3,3,4,4-tetracyanocycloheptene,1,2,3,4-tetracyanocyclooctene, 3,3,4,4-tetracyanocyclooctene, tricyclo[4.2.2.0(2,5)]deca-3,9-diene-7,7,8,8-tetracarbonitrile,1,2,6,7-tetracyanocyclooctene, tricyclo[4.2.2.0(2,5)]deca-3,9-diene-7,7,8,8-tetracarbonitrile, 3-methyltricyclo[4.2.2.0(2,5)]deca-3,9-diene-7,7,8,8-tetracarbonitrile, 3-phenyltricyclo[4.2.2.0(2,5)]deca-3,9-diene-7,7,8,8-tetracarbonitrile,3,4-dimethyltricyclo[4.2.2.0(2,5)]deca-3,9-diene-7,7,8,8-tetracarbonitrile, bicyclo[7.2.0]undeca-2,4,7-triene-10,10,11,11-tetracarbonitrile, bicyclo[2.2.1]hept-5-ene-2,2,3,3-tetracarbonitrile, and tetracyclo[8.2.2.0(2,9).0(3,8)]tetradeca-3(8),13-diene-11,11,12,12-tetracarbonitrile.

The amount of the polycyano compound that can be added to thepolymerization mixture to yield the functionalized polymer of thisinvention may depend on various factors including the type and amount ofcatalyst or initiator used to synthesize the reactive polymer and thedesired degree of functionalization. In one or more embodiments, wherethe reactive polymer is prepared by employing a lanthanide-basedcatalyst, the amount of the polycyano compound employed can be describedwith reference to the lanthanide metal of the lanthanide-containingcompound. For example, the molar ratio of the polycyano compound to thelanthanide metal may be from about 1:1 to about 200:1, in otherembodiments from about 5:1 to about 150:1, and in other embodiments fromabout 10:1 to about 100:1.

In other embodiments, such as where the reactive polymer is prepared byusing an anionic initiator, the amount of the polycyano compoundemployed can be described with reference to the amount of metal cationassociated with the initiator. For example, where an organolithiuminitiator is employed, the molar ratio of the polycyano compound to thelithium cation may be from about 0.3:1 to about 2:1, in otherembodiments from about 0.6:1 to about 1.5:1, and in other embodimentsfrom 0.8:1 to about 1.2:1.

In one or more embodiments, in addition to the polycyano compound, aco-functionalizing agent may also be added to the polymerization mixtureto yield a functionalized polymer with tailored properties. A mixture oftwo or more co-functionalizing agents may also be employed. Theco-functionalizing agent may be added to the polymerization mixtureprior to, together with, or after the introduction of the polycyanocompound. In one or more embodiments, the co-functionalizing agent isadded to the polymerization mixture at least 5 minutes after, in otherembodiments at least 10 minutes after, and in other embodiments at least30 minutes after the introduction of the polycyano compound.

In one or more embodiments, co-functionalizing agents include compoundsor reagents that can react with a reactive polymer produced by thisinvention and thereby provide the polymer with a functional group thatis distinct from a propagating chain that has not been reacted with theco-functionalizing agent. The functional group may be reactive orinteractive with other polymer chains (propagating and/ornon-propagating) or with other constituents such as reinforcing fillers(e.g. carbon black) that may be combined with the polymer. In one ormore embodiments, the reaction between the co-functionalizing agent andthe reactive polymer proceeds via an addition or substitution reaction.

Useful co-functionalizing agents may include compounds that simplyprovide a functional group at the end of a polymer chain without joiningtwo or more polymer chains together, as well as compounds that cancouple or join two or more polymer chains together via a functionallinkage to form a single macromolecule. The latter type ofco-functionalizing agents may also be referred to as coupling agents.

In one or more embodiments, co-functionalizing agents include compoundsthat will add or impart a heteroatom to the polymer chain. In particularembodiments, co-functionalizing agents include those compounds that willimpart a functional group to the polymer chain to form a functionalizedpolymer that reduces the 50° C. hysteresis loss of a carbon-black filledvulcanizates prepared from the functionalized polymer as compared tosimilar carbon-black filled vulcanizates prepared fromnon-functionalized polymer. In one or more embodiments, this reductionin hysteresis loss is at least 5%, in other embodiments at least 10%,and in other embodiments at least 15%.

In one or more embodiments, suitable co-functionalizing agents includethose compounds that contain groups that may react with the reactivepolymers produced in accordance with this invention. Exemplaryco-functionalizing agents include ketones, quinones, aldehydes, amides,esters, isocyanates, isothiocyanates, epoxides, imines, aminoketones,aminothioketones, and acid anhydrides. Examples of these compounds aredisclosed in U.S. Pat. Nos. 4,906,706, 4,990,573, 5,064,910, 5,567,784,5,844,050, 6838,526, 6977,281, and 6,992,147; U.S. Pat. Publication Nos.2006/0004131 A1, 2006/0025539 A1, 2006/0030677 A1, and 2004/0147694 A1;Japanese Patent Application Nos. 05-051406A, 05-059103A, 10-306113A, and11-035633A; which are incorporated herein by reference. Other examplesof co-functionalizing agents include azine compounds as described inU.S. Ser. No. 11/640,711, hydrobenzamide compounds as disclosed in U.S.Ser. No. 11/710,713, nitro compounds as disclosed in U.S. Ser. No.11/710,845, and protected oxime compounds as disclosed in U.S. Ser. No.60/875,484, all of which are incorporated herein by reference.

In particular embodiments, the co-functionalizing agents employed may bemetal halides, metalloid halides, alkoxysilanes, metal carboxylates,hydrocarbylmetal carboxylates, hydrocarbylmetal ester-carboxylates, andmetal alkoxides.

Exemplary metal halide compounds include tin tetrachloride, tintetrabromide, tin tetraiodide, n-butyltin trichloride, phenyltintrichloride, di-n-butyltin dichloride, diphenyltin dichloride,tri-n-butyltin chloride, triphenyltin chloride, germanium tetrachloride,germanium tetrabromide, germanium tetraiodide, n-butylgermaniumtrichloride, di-n-butylgermanium dichloride, and tri-n-butylgermaniumchloride.

Exemplary metalloid halide compounds include silicon tetrachloride,silicon tetrabromide, silicon tetraiodide, methyltrichlorosilane,phenyltrichlorosilane, dimethyldichlorosilane, diphenyldichlorosilane,boron trichloride, boron tribromide, boron triiodide, phosphoroustrichloride, phosphorous tribromide, and phosphorus triiodide.

In one or more embodiments, the alkoxysilanes may include at least onegroup selected from the group consisting of an epoxy group and anisocyanate group.

Exemplary alkoxysilane compounds including an epoxy group include(3-glycidyloxypropyl)trimethoxysilane,(3-glycidyloxypropyl)triethoxysilane,(3-glycidyloxypropyl)triphenoxysilane,(3-glycidyloxypropyl)methyldimethoxysilane,(3-glycidyloxypropyl)methyldiethoxysilane,(3-glycidyloxypropyl)methyldiphenoxysilane,[2-(3,4-epoxycyclohexyl)ethyl]trimethoxysilane, and[2-(3,4-epoxycyclohexyl)ethyl]triethoxysilane.

Exemplary alkoxysilane compounds including an isocyanate group include(3-isocyanatopropyl)trimethoxysilane,(3-isocyanatopropyl)triethoxysilane,(3-isocyanatopropyl)triphenoxysilane,(3-isocyanatopropyl)methyldimethoxysilane,(3-isocyanatopropyl)methyldiethoxysilane(3-isocyanatopropyl)methyldiphenoxysilane,and (isocyanatomethyl)methyldimethoxysilane.

Exemplary metal carboxylate compounds include tin tetraacetate, tinbis(2-ethylhexanaote), and tin bis(neodecanoate).

Exemplary hydrocarbylmetal carboxylate compounds include triphenyltin2-ethylhexanoate, tri-n-butyltin 2-ethylhexanoate, tri-n-butyltinneodecanoate, triisobutyltin 2-ethylhexanoate, diphenyltinbis(2-ethylhexanoate), di-n-butyltin bis(2-ethylhexanoate),di-n-butyltin bis(neodecanoate), phenyltin tris(2-ethylhexanoate), andn-butylltin tris(2-ethylhexanoate).

Exemplary hydrocarbylmetal ester-carboxylate compounds includedi-n-butyltin bis(n-octylmaleate), di-n-octyltin bis(n-octylmaleate),diphenyltin bis(n-octylmaleate), di-n-butyltin bis(2-ethylhexylmaleate),di-n-octyltin bis(2-ethylhexylmaleate), and diphenyltinbis(2-ethylhexylmaleate).

Exemplary metal alkoxide compounds include dimethoxytin, diethoxytin,tetraethoxytin, tetra-n-propoxytin, tetraisopropoxytin,tetra-n-butoxytin, tetraisobutoxytin, tetra-t-butoxytin, andtetraphenoxytin.

The amount of the co-functionalizing agent that can be added to thepolymerization mixture may depend on various factors including the typeand amount of catalyst or initiator used to synthesize the reactivepolymer and the desired degree of functionalization. In one or moreembodiments, where the reactive polymer is prepared by employing alanthanide-based catalyst, the amount of the co-functionalizing agentemployed can be described with reference to the lanthanide metal of thelanthanide-containing compound. For example, the molar ratio of theco-functionalizing agent to the lanthanide metal may be from about 1:1to about 200:1, in other embodiments from about 5:1 to about 150:1, andin other embodiments from about 10:1 to about 100:1.

In other embodiments, such as where the reactive polymer is prepared byusing an anionic initiator, the amount of the co-functionalizing agentemployed can be described with reference to the amount of metal cationassociated with the initiator. For example, where an organolithiuminitiator is employed, the molar ratio of the co-functionalizing agentto the lithium cation may be from about 0.3:1 to about 2:1, in otherembodiments from about 0.6:1 to about 1.5:1, and in other embodimentsfrom 0.8:1 to about 1.2:1.

The amount of the co-functionalizing agent employed can also bedescribed with reference to the polycyano compound. In one or moreembodiments, the molar ratio of the co-functionalizing agent to thepolycyano compound may be from about 0.05:1 to about 1:1, in otherembodiments from about 0.1:1 to about 0.8:1, and in other embodimentsfrom about 0.2:1 to about 0.6:1.

In one or more embodiments, the polycyano compound (and optionally theco-functionalizing agent) may be introduced to the polymerizationmixture at a location (e.g., within a vessel) where the polymerizationhas been conducted. In other embodiments, the polycyano compound may beintroduced to the polymerization mixture at a location that is distinctfrom where the polymerization has taken place. For example, thepolycyano compound may be introduced to the polymerization mixture indownstream vessels including downstream reactors or tanks, in-linereactors or mixers, extruders, or devolatilizers.

In one or more embodiments, the polycyano compound (and optionally theco-functionalizing agent) can be reacted with the reactive polymer aftera desired monomer conversion is achieved but before the polymerizationmixture is quenched by a quenching agent. In one or more embodiments,the reaction between the polycyano compound and the reactive polymer maytake place within 30 minutes, in other embodiments within 5 minutes, andin other embodiments within one minute after the peak polymerizationtemperature is reached. In one or more embodiments, the reaction betweenthe polycyano compound and the reactive polymer can occur once the peakpolymerization temperature is reached. In other embodiments, thereaction between the polycyano compound and the reactive polymer canoccur after the reactive polymer has been stored. In one or moreembodiments, the storage of the reactive polymer occurs at roomtemperature or below room temperature under an inert atmosphere. In oneor more embodiments, the reaction between the polycyano compound and thereactive polymer may take place at a temperature from about 10° C. toabout 150° C., and in other embodiments from about 20° C. to about 100°C. The time required for completing the reaction between the polycyanocompound and the reactive polymer depends on various factors such as thetype and amount of the catalyst or initiator used to prepare thereactive polymer, the type and amount of the polycyano compound, as wellas the temperature at which the functionalization reaction is conducted.In one or more embodiments, the reaction between the polycyano compoundand the reactive polymer can be conducted for about 10 to 60 minutes.

In one or more embodiments, after the reaction between the reactivepolymer and the polycyano compound (and optionally theco-functionalizing agent) has been accomplished or completed, aquenching agent can be added to the polymerization mixture in order toprotonate the reaction product between the reactive polymer and thepolycyano compound, inactivate any residual reactive polymer chains,and/or inactivate the catalyst or catalyst components. The quenchingagent may include a protic compound, which includes, but is not limitedto, an alcohol, a carboxylic acid, an inorganic acid, water, or amixture thereof. An antioxidant such as 2,6-di-tert-butyl-4-methylphenolmay be added along with, before, or after the addition of the quenchingagent. The amount of the antioxidant employed may be in the range of0.2% to 1% by weight of the polymer product. Additionally, the polymerproduct can be oil extended by adding an oil to the polymer, which maybe in the form of a polymer cement or polymer dissolved or suspended inmonomer. Practice of the present invention does not limit the amount ofoil that may be added, and therefore conventional amounts may be added(e.g., 5-50 phr). Useful oils or extenders that may be employed include,but are not limited to, aromatic oils, paraffinic oils, naphthenic oils,vegetable oils other than castor oils, low PCA oils including MES, TDAE,and SRAE, and heavy naphthenic oils.

Once the polymerization mixture has been quenched, the variousconstituents of the polymerization mixture may be recovered. In one ormore embodiments, the unreacted monomer can be recovered from thepolymerization mixture. For example, the monomer can be distilled fromthe polymerization mixture by using techniques known in the art. In oneor more embodiments, a devolatilizer may be employed to remove themonomer from the polymerization mixture. Once the monomer has beenremoved from the polymerization mixture, the monomer may be purified,stored, and/or recycled back to the polymerization process.

The polymer product may be recovered from the polymerization mixture byusing techniques known in the art. In one or more embodiments,desolventization and drying techniques may be used. For instance, thepolymer can be recovered by passing the polymerization mixture through aheated screw apparatus, such as a desolventizing extruder, in which thevolatile substances are removed by evaporation at appropriatetemperatures (e.g., about 100° C. to about 170° C.) and underatmospheric or sub-atmospheric pressure. This treatment serves to removeunreacted monomer as well as any low-boiling solvent. Alternatively, thepolymer can also be recovered by subjecting the polymerization mixtureto steam desolventization, followed by drying the resulting polymercrumbs in a hot air tunnel. The polymer can also be recovered bydirectly drying the polymerization mixture on a drum dryer.

While the reactive polymer and the polycyano compound (and optionallythe co-functionalizing agent) are believed to react to produce a novelfunctionalized polymer, which can be protonated or further modified, theexact chemical structure of the functionalized polymer produced in everyembodiment is not known with any great degree of certainty, particularlyas the structure relates to the residue imparted to the polymer chainend by the polycyano compound and optionally the co-functionalizingagent. Indeed, it is speculated that the structure of the functionalizedpolymer may depend upon various factors such as the conditions employedto prepare the reactive polymer (e.g., the type and amount of thecatalyst or initiator) and the conditions employed to react thepolycyano compound (and optionally the co-functionalizing agent) withthe reactive polymer (e.g., the types and amounts of the polycyanocompound and the co-functionalizing agent).

In one or more embodiments, one of the products resulting from thereaction between the polycyano compound and the reactive polymer,particularly after quenching, may be a functionalized polymer defined byone of the formulae:

where π is a polymer chain and R¹ is a divalent organic group as definedabove.

It is believed that the functionalized polymers described by the aboveformulae may, upon exposure to moisture, convert to functionalizedpolymers that have a ketone-type structure and that may be defined byone of the formulae:

where π is a polymer chain and R¹ is a divalent organic group as definedabove.

In one or more embodiments, the functionalized polymers preparedaccording to this invention may contain unsaturation. In these or otherembodiments, the functionalized polymers are vulcanizable. In one ormore embodiments, the functionalized polymers can have a glasstransition temperature (T_(g)) that is less than 0° C., in otherembodiments less than −20° C., and in other embodiments less than −30°C. In one embodiment, these polymers may exhibit a single glasstransition temperature. In particular embodiments, the polymers may behydrogenated or partially hydrogenated.

In one or more embodiments, the functionalized polymers of thisinvention may be cis-1,4-polydienes having a cis-1,4-linkage contentthat is greater than 60%, in other embodiments greater than about 75%,in other embodiments greater than about 90%, and in other embodimentsgreater than about 95%, where the percentages are based upon the numberof diene mer units adopting the cis-1,4 linkage versus the total numberof diene mer units. Also, these polymers may have a 1,2-linkage contentthat is less than about 7%, in other embodiments less than 5%, in otherembodiments less than 2%, and in other embodiments less than 1%, wherethe percentages are based upon the number of diene mer units adoptingthe 1,2-linkage versus the total number of diene mer units. The balanceof the diene mer units may adopt the trans-1,4-linkage. The cis-1,4-,1,2-, and trans-1,4-linkage contents can be determined by infraredspectroscopy. The number average molecular weight (M_(n)) of thesepolymers may be from about 1,000 to about 1,000,000, in otherembodiments from about 5,000 to about 200,000, in other embodiments fromabout 25,000 to about 150,000, and in other embodiments from about50,000 to about 120,000, as determined by using gel permeationchromatography (GPC) calibrated with polystyrene standards andMark-Houwink constants for the polymer in question. The molecular weightdistribution or polydispersity (M_(w)/M_(n)) of these polymers may befrom about 1.5 to about 5.0, and in other embodiments from about 2.0 toabout 4.0.

Advantageously, the functionalized polymers of this invention mayexhibit improved cold-flow resistance and provide rubber compositionsthat demonstrate reduced hysteresis. The functionalized polymers areparticularly useful in preparing rubber compositions that can be used tomanufacture tire components. Rubber compounding techniques and theadditives employed therein are generally disclosed in The Compoundingand Vulcanization of Rubber, in Rubber Technology (2′ Ed. 1973).

The rubber compositions can be prepared by using the functionalizedpolymers alone or together with other elastomers (i.e., polymers thatcan be vulcanized to form compositions possessing rubbery or elastomericproperties). Other elastomers that may be used include natural andsynthetic rubbers. The synthetic rubbers typically derive from thepolymerization of conjugated diene monomers, the copolymerization ofconjugated diene monomers with other monomers such as vinyl-substitutedaromatic monomers, or the copolymerization of ethylene with one or moreα-olefins and optionally one or more diene monomers.

Exemplary elastomers include natural rubber, synthetic polyisoprene,polybutadiene, polyisobutylene-co-isoprene, neoprene,poly(ethylene-co-propylene), poly(styrene-co-butadiene),poly(styrene-co-isoprene), poly(styrene-co-isoprene-co-butadiene),poly(isoprene-co-butadiene), poly(ethylene-co-propylene-co-diene),polysulfide rubber, acrylic rubber, urethane rubber, silicone rubber,epichlorohydrin rubber, and mixtures thereof. These elastomers can havea myriad of macromolecular structures including linear, branched, andstar-shaped structures.

The rubber compositions may include fillers such as inorganic andorganic fillers. Examples of organic fillers include carbon black andstarch. Examples of inorganic fillers include silica, aluminumhydroxide, magnesium hydroxide, mica, talc (hydrated magnesiumsilicate), and clays (hydrated aluminum silicates). Carbon blacks andsilicas are the most common fillers used in manufacturing tires. Incertain embodiments, a mixture of different fillers may beadvantageously employed.

In one or more embodiments, carbon blacks include furnace blacks,channel blacks, and lamp blacks. More specific examples of carbon blacksinclude super abrasion furnace blacks, intermediate super abrasionfurnace blacks, high abrasion furnace blacks, fast extrusion furnaceblacks, fine furnace blacks, semi-reinforcing furnace blacks, mediumprocessing channel blacks, hard processing channel blacks, conductingchannel blacks, and acetylene blacks.

In particular embodiments, the carbon blacks may have a surface area(EMSA) of at least 20 m²/g and in other embodiments at least 35 m²/g;surface area values can be determined by ASTM D-1765 using thecetyltrimethylammonium bromide (CTAB) technique. The carbon blacks maybe in a pelletized form or an unpelletized flocculent form. Thepreferred form of carbon black may depend upon the type of mixingequipment used to mix the rubber compound.

The amount of carbon black employed in the rubber compositions can be upto about 50 parts by weight per 100 parts by weight of rubber (phr),with about 5 to about 40 phr being typical.

Some commercially available silicas which may be used include Hi-Sil™215, Hi-Sil™ 233, and Hi-Sil™ 190 (PPG Industries, Inc.; Pittsburgh,Pa.). Other suppliers of commercially available silica include GraceDavison (Baltimore, Md.), Degussa Corp. (Parsippany, N.J.), RhodiaSilica Systems (Cranbury, N.J.), and J.M. Huber Corp. (Edison, N.J.).

In one or more embodiments, silicas may be characterized by theirsurface areas, which give a measure of their reinforcing character. TheBrunauer, Emmet and Teller (“BET”) method (described in J. Am. Chem.Soc., vol. 60, p. 309 et seq.) is a recognized method for determiningthe surface area. The BET surface area of silica is generally less than450 m²/g. Useful ranges of surface area include from about 32 to about400 m²/g, about 100 to about 250 m²/g, and about 150 to about 220 m²/g.

The pH's of the silicas are generally from about 5 to about 7 orslightly over 7, or in other embodiments from about 5.5 to about 6.8.

In one or more embodiments, where silica is employed as a filler (aloneor in combination with other fillers), a coupling agent and/or ashielding agent may be added to the rubber compositions during mixing inorder to enhance the interaction of silica with the elastomers. Usefulcoupling agents and shielding agents are disclosed in U.S. Pat. Nos.3,842,111, 3,873,489, 3,978,103, 3,997,581, 4,002,594, 5,580,919,5,583,245, 5,663,396, 5,674,932, 5,684,171, 5,684,172 5,696,197,6,608,145, 6,667,362, 6,579,949, 6,590,017, 6,525,118, 6,342,552, and6,683,135, which are incorporated herein by reference.

The amount of silica employed in the rubber compositions can be fromabout 1 to about 100 phr or in other embodiments from about 5 to about80 phr. The useful upper range is limited by the high viscosity impartedby silicas. When silica is used together with carbon black, the amountof silica can be decreased to as low as about 1 phr; as the amount ofsilica is decreased, lesser amounts of coupling agents and shieldingagents can be employed. Generally, the amounts of coupling agents andshielding agents range from about 4% to about 20% based on the weight ofsilica used.

A multitude of rubber curing agents (also called vulcanizing agents) maybe employed, including sulfur or peroxide-based curing systems. Curingagents are described in Kirk-Othmer, ENCYCLOPEDIA OF CHEMICALTECHNOLOGY, Vol. 20, pgs. 365-468, (3^(rd) Ed. 1982), particularlyVulcanization Agents and Auxiliary Materials, pgs. 390-402, and A. Y.Coran, Vulcanization, ENCYCLOPEDIA OF POLYMER SCIENCE AND ENGINEERING,(2^(nd) Ed. 1989), which are incorporated herein by reference.Vulcanizing agents may be used alone or in combination.

Other ingredients that are typically employed in rubber compounding mayalso be added to the rubber compositions. These include accelerators,accelerator activators, oils, plasticizer, waxes, scorch inhibitingagents, processing aids, zinc oxide, tackifying resins, reinforcingresins, fatty acids such as stearic acid, peptizers, and antidegradantssuch as antioxidants and antiozonants. In particular embodiments, theoils that are employed include those conventionally used as extenderoils, which are described above.

All ingredients of the rubber compositions can be mixed with standardmixing equipment such as Banbury or Brabender mixers, extruders,kneaders, and two-rolled mills. In one or more embodiments, theingredients are mixed in two or more stages. In the first stage (oftenreferred to as the masterbatch mixing stage), a so-called masterbatch,which typically includes the rubber component and filler, is prepared.To prevent premature vulcanization (also known as scorch), themasterbatch may exclude vulcanizing agents. The masterbatch may be mixedat a starting temperature of from about 25° C. to about 125° C. with adischarge temperature of about 135° C. to about 180° C. Once themasterbatch is prepared, the vulcanizing agents may be introduced andmixed into the masterbatch in a final mixing stage, which is typicallyconducted at relatively low temperatures so as to reduce the chances ofpremature vulcanization. Optionally, additional mixing stages, sometimescalled remills, can be employed between the masterbatch mixing stage andthe final mixing stage. One or more remill stages are often employedwhere the rubber composition includes silica as the filler. Variousingredients including the functionalized polymers of this invention canbe added during these remills.

The mixing procedures and conditions particularly applicable tosilica-filled tire formulations are described in U.S. Pat. Nos.5,227,425, 5,719,207, and 5,717,022, as well as European Patent No.890,606, all of which are incorporated herein by reference. In oneembodiment, the initial masterbatch is prepared by including thefunctionalized polymer of this invention and silica in the substantialabsence of coupling agents and shielding agents.

The rubber compositions prepared from the functionalized polymers ofthis invention are particularly useful for forming tire components suchas treads, subtreads, sidewalls, body ply skims, bead filler, and thelike. Preferably, the functional polymers of this invention are employedin tread and sidewall formulations. In one or more embodiments, thesetread or sidewall formulations may include from about 10% to about 100%by weight, in other embodiments from about 35% to about 90% by weight,and in other embodiments from about 50% to about 80% by weight of thefunctionalized polymer based on the total weight of the rubber withinthe formulation.

Where the rubber compositions are employed in the manufacture of tires,these compositions can be processed into tire components according toordinary tire manufacturing techniques including standard rubbershaping, molding and curing techniques. Typically, vulcanization iseffected by heating the vulcanizable composition in a mold; e.g., it maybe heated to about 140° C. to about 180° C. Cured or crosslinked rubbercompositions may be referred to as vulcanizates, which generally containthree-dimensional polymeric networks that are thermoset. The otheringredients, such as fillers and processing aids, may be evenlydispersed throughout the crosslinked network. Pneumatic tires can bemade as discussed in U.S. Pat. Nos. 5,866,171, 5,876,527, 5,931,211, and5,971,046, which are incorporated herein by reference.

In order to demonstrate the practice of the present invention, thefollowing examples have been prepared and tested. The examples shouldnot, however, be viewed as limiting the scope of the invention. Theclaims will serve to define the invention.

EXAMPLES Example 1 Synthesis of Unmodified cis-1,4-Polybutadiene

To a 2-gallon nitrogen-purged reactor equipped with turbine agitatorblades were added 1383 g of hexane and 3083 g of 20.6 wt % 1,3-butadienein hexane. A preformed catalyst was prepared by mixing 7.35 ml of 4.32Mmethylaluminoxane in toluene, 1.83 g of 20.6 wt % 1,3-butadiene inhexane, 0.59 ml of 0.537M neodymium versatate in cyclohexane, 6.67 ml of1.0M diisobutylaluminum hydride in hexane, and 1.27 ml of 1.0Mdiethylaluminum chloride in hexane. The catalyst was aged for 15 minutesand charged into the reactor. The reactor jacket temperature was thenset to 65° C. About 60 minutes after addition of the catalyst, thepolymerization mixture was cooled to room temperature and quenched with30 ml of 12 wt % 2,6-di-tert-butyl-4-methylphenol solution inisopropanol. The resulting polymer cement was coagulated with 12 litersof isopropanol containing 5 g of 2,6-di-tert-butyl-4-methylphenol andthen drum-dried. The Mooney viscosity (ML₁₋₄) of the resulting polymerwas determined to be 26.5 at 100° C. by using a Alpha TechnologiesMooney viscometer with a large rotor, a one-minute warm-up time, and afour-minute running time. As determined by gel permeation chromatography(GPC), the polymer had a number average molecular weight (M_(n)) of109,400, a weight average molecular weight (M_(w)) of 221,900, and amolecular weight distribution (M_(w)/M_(n)) of 2.03. The infraredspectroscopic analysis of the polymer indicated a cis-1,4-linkagecontent of 94.4%, a trans-1,4-linkage content of 5.1%, and a 1,2-linkagecontent of 0.5%.

The cold-flow resistance of the polymer was measured by using a Scottplasticity tester. Approximately 2.5 g of the polymer was molded, at100° C. for 20 minutes, into a cylindrical button with a diameter of 15mm and a height of 12 mm. After cooling down to room temperature, thebutton was removed from the mold and placed in a Scott plasticity testerat room temperature. A 5-kg load was applied to the specimen. After 8minutes, the residual gauge (i.e., sample thickness) was measured andtaken as an indication of the cold-flow resistance of the polymer.Generally, a higher residual gauge value indicates better cold-flowresistance.

The properties of the unmodified cis-1,4-polybutadiene are summarized inTable 1.

TABLE 1 PHYSICAL PROPERTIES OF CIS-1,4-POLYBUTADIENE Example No. Example1 Example 2 Example 3 Example 4 Example 5 Example 6 Polymer typeunmodified unmodified 1,2-DCNB- 1,2-DCNE- 1,3-DCNP- ADPN- modifiedmodified modified modified ML₁₊₄ at 100° C. 26.5 44.1 43.3 63.3 32.536.2 M_(n) 109,400 137,900 45,900 47,800 91,400 81,300 M_(w) 221,900248,700 162,100 184,300 194,800 181,000 M_(w)/M_(n) 2.03 1.80 3.53 3.862.13 2.23 % cis-1,4 94.4 95.0 94.0 94.0 94.0 94.0 % trans-1,4 5.1 4.55.5 5.5 5.5 5.5 % 1,2 0.5 0.5 0.5 0.5 0.5 0.5 Cold-flow gauge 1.67 2.193.47 4.22 2.21 2.35 (mm at 8 min.) Example No. Example 9 Example 10Example 7 Example 8 (comparative) (comparative) Polymer typeBZMN-modified FMN-modified PhCN-modified CH₃CN-modified ML₁₊₄ at 100° C.27.7 68.9 29.1 33.4 M_(n) 96,100 111.4 112,000 114,500 M_(w) 204,100235.6 202,700 208,400 M_(w)/M_(n) 2.12 2.12 1.81 1.82 % cis-1,4 94.094.0 94.4 94.5 % trans-1,4 5.5 5.0 5.0 4.9 % 1,2 0.5 0.5 0.6 0.6Cold-flow gauge 1.93 4.03 1.95 2.08 (mm at 8 min.)

Example 2 Synthesis of Unmodified cis-1,4-Polybutadiene

To a 2-gallon nitrogen-purged reactor equipped with turbine agitatorblades were added 1631 g of hexane and 2835 g of 22.4 wt % 1,3-butadienein hexane. A preformed catalyst was prepared by mixing 6.10 ml of 4.32Mmethylaluminoxane in toluene, 1.27 g of 22.4 wt % 1,3-butadiene inhexane, 0.49 ml of 0.537M neodymium versatate in cyclohexane, 5.53 ml of1.0M diisobutylaluminum hydride in hexane, and 1.05 ml of 1.0Mdiethylaluminum chloride in hexane. The catalyst was aged for 15 minutesand charged into the reactor. The reactor jacket temperature was thenset to 65° C. About 72 minutes after addition of the catalyst, thepolymerization mixture was cooled to room temperature and quenched with30 ml of 12 wt % 2,6-di-tert-butyl-4-methylphenol solution inisopropanol. The resulting polymer cement was coagulated with 12 litersof isopropanol containing 5 g of 2,6-di-tert-butyl-4-methylphenol andthen drum-dried. The properties of the resulting polymer are summarizedin Table 1.

Example 3 Synthesis of cis-1,4-Polybutadiene Modified with1,2-Dicyanobenzene (1,2-DCNB)

To a 2-gallon nitrogen-purged reactor equipped with turbine agitatorblades were added 1579 g of hexane and 2886 g of 22.0 wt % 1,3-butadienein hexane. A preformed catalyst was prepared by mixing 9.55 ml of 4.32Mmethylaluminoxane in toluene, 2.03 g of 22.0 wt % 1,3-butadiene inhexane, 0.77 ml of 0.537M neodymium versatate in cyclohexane, 8.67 ml of1.0M diisobutylaluminum hydride in hexane, and 1.65 ml of 1.0Mdiethylaluminum chloride in hexane. The catalyst was aged for 15 minutesand charged into the reactor. The reactor jacket temperature was thenset to 65° C. About 50 minutes after addition of the catalyst, thepolymerization mixture was cooled to room temperature.

About 351 g of the resulting unmodified polymer cement (i.e.,pseudo-living polymer cement) was transferred from the reactor to anitrogen-purged bottle, followed by addition of 14.3 ml of 0.165M1,2-dicyanobenzene (1,2-DCNB) in toluene. The bottle was tumbled for 30minutes in a water bath maintained at 65° C. The resulting polymercement was quenched with 3 ml of 12 wt %2,6-di-tert-butyl-4-methylphenol solution in isopropanol, coagulatedwith 2 liters of isopropanol containing 0.5 g of2,6-di-tert-butyl-4-methylphenol, and then drum-dried. The properties ofthe resulting 1,2-DCNB-modified polymer are summarized in Table 1.

Example 4 Synthesis of cis-1,4-Polybutadiene Modified with1,2-Dicyanoethane(1,2-DCNE)

About 368 g of the pseudo-living polymer cement as synthesized inExample 3 was transferred from the reactor to a nitrogen-purged bottle,followed by addition of 5.91 ml of 0.419M 1,2-dicyanoethane(1,2-DCNE) intoluene. The bottle was tumbled for 30 minutes in a water bathmaintained at 65° C. The resulting polymer cement was quenched with 3 mlof 12 wt % 2,6-di-tert-butyl-4-methylphenol solution in isopropanol,coagulated with 2 liters of isopropanol containing 0.5 g of2,6-di-tert-butyl-4-methylphenol, and then drum-dried. The properties ofthe resulting 1,2-DCNE-modified polymer are summarized in Table 1.

Example 5 Synthesis of cis-1,4-Polybutadiene Modified with1,3-Dicyanopropane(1,3-DCNP)

About 346 g of the pseudo-living polymer cement as synthesized inExample 3 was transferred from the reactor to a nitrogen-purged bottle,followed by addition of 4.49 ml of 0.519M 1,3-dicyanopropane(1,3-DCNP,also known as glutaronitrile) in toluene. The bottle was tumbled for 30minutes in a water bath maintained at 65° C. The resulting polymercement was quenched with 3 ml of 12 wt %2,6-di-tert-butyl-4-methylphenol solution in isopropanol, coagulatedwith 2 liters of isopropanol containing 0.5 g of2,6-di-tert-butyl-4-methylphenol, and then drum-dried. The properties ofthe resulting 1,3-DCNP-modified polymer are summarized in Table 1.

Example 6 Synthesis of cis-1,4-Polybutadiene Modified with Adiponitrile(ADPN)

About 360 g of the pseudo-living polymer cement as synthesized inExample 3 was transferred from the reactor to a nitrogen-purged bottle,followed by addition of 6.13 ml of 0.427M adiponitrile (ADPN, also knownas 1,4-dicyanobutane) in toluene. The bottle was tumbled for 30 minutesin a water bath maintained at 65° C. The resulting polymer cement wasquenched with 3 ml of 12 wt % 2,6-di-tert-butyl-4-methylphenol solutionin isopropanol, coagulated with 2 liters of isopropanol containing 0.5 gof 2,6-di-tert-butyl-4-methylphenol, and then drum-dried. The propertiesof the resulting ADPN-modified polymer are summarized in Table 1.

Example 7 Synthesis of cis-1,4-Polybutadiene Modified withBenzylidenemalononitrile (BZMN)

About 350 g of the pseudo-living polymer cement as synthesized inExample 3 was transferred from the reactor to a nitrogen-purged bottle,followed by addition of 4.52 ml of 0.520M benzylidenemalononitrile(BZMN) in toluene. The bottle was tumbled for 30 minutes in a water bathmaintained at 65° C. The resulting polymer cement was quenched with 3 mlof 12 wt % 2,6-di-tert-butyl-4-methylphenol solution in isopropanol,coagulated with 2 liters of isopropanol containing 0.5 g of2,6-di-tert-butyl-4-methylphenol, and then drum-dried. The properties ofthe resulting BZMN-modified polymer are summarized in Table 1.

Example 8 Synthesis of cis-1,4-Polybutadiene Modified with Fumaronitrile(FMN)

About 347 g of the pseudo-living polymer cement as synthesized inExample 3 was transferred from the reactor to a nitrogen-purged bottle,followed by addition of 1.34 ml of 0.470M fumaronitrile (FMN, also knownas trans-1,2-dicyanoethylene) in toluene. The bottle was tumbled for 30minutes in a water bath maintained at 65° C. The resulting polymercement was quenched with 3 ml of 12 wt %2,6-di-tert-butyl-4-methylphenol solution in isopropanol, coagulatedwith 2 liters of isopropanol containing 0.5 g of2,6-di-tert-butyl-4-methylphenol, and then drum-dried. The properties ofthe resulting FMN-modified polymer are summarized in Table 1.

Example 9 Synthesis of cis-1,4-Polybutadiene Modified with Benzonitrile(PhCN)

To a 2-gallon nitrogen-purged reactor equipped with turbine agitatorblades were added 1540 g of hexane and 2926 g of 21.7 wt % 1,3-butadienein hexane. A preformed catalyst was prepared by mixing 8.08 ml of 4.32Mmethylaluminoxane in toluene, 1.74 g of 21.7 wt % 1,3-butadiene inhexane, 0.65 ml of 0.537M neodymium versatate in cyclohexane, 7.33 ml of1.0M diisobutylaluminum hydride in hexane, and 1.40 ml of 1.0Mdiethylaluminum chloride in hexane. The catalyst was aged for 15 minutesand charged into the reactor. The reactor jacket temperature was thenset to 65° C. About 55 minutes after addition of the catalyst, thepolymerization mixture was cooled to room temperature.

About 423 g of the resulting unmodified polymer cement (i.e.,pseudo-living polymer cement) was transferred from the reactor to anitrogen-purged bottle, followed by addition of 4.03 ml of 0.676Mbenzonitrile (PhCN) in toluene. The bottle was tumbled for 30 minutes ina water bath maintained at 65° C. The resulting polymer cement wasquenched with 3 ml of 12 wt % 2,6-di-tert-butyl-4-methylphenol solutionin isopropanol, coagulated with 2 liters of isopropanol containing 0.5 gof 2,6-di-tert-butyl-4-methylphenol, and then drum-dried. The propertiesof the resulting PhCN-modified polymer are summarized in Table 1.

Example 10 Synthesis of cis-1,4-Polybutadiene Modified with Acetonitrile(CH₃CN)

About 437 g of the pseudo-living polymer cement as synthesized inExample 9 was transferred from the reactor to a nitrogen-purged bottle,followed by addition of 5.00 ml of 0.539M acetonitrile (CH₃CN) intoluene. The bottle was tumbled for 30 minutes in a water bathmaintained at 65° C. The resulting polymer cement was quenched with 3 mlof 12 wt % 2,6-di-tert-butyl-4-methylphenol solution in isopropanol,coagulated with 2 liters of isopropanol containing 0.5 g of2,6-di-tert-butyl-4-methylphenol, and then drum-dried. The properties ofthe resulting CH₃CN-modified polymer are summarized in Table 1.

In FIG. 1, the cold-flow resistance of the cis-1,4-polybutadiene samplessynthesized in Examples 1-10 is plotted against the polymer Mooneyviscosity. The data indicate that, at the same polymer Mooney viscosity,the 1,2-DCNB-, 1,2-DCNE-, 1,3-DCNP-, ADPN-, and FMN-modifiedcis-1,4-polybutadiene samples show higher residual cold-flow gaugevalues and accordingly better cold-flow resistance than the unmodifiedpolymer. In contrast, both PhCN- and CH₃CN-modifiedcis-1,4-polybutadiene samples provide no or very marginal improvement incold-flow resistance as compared to the unmodified polymer.

Examples 11-20 Compounding Evaluation of 1,2-DCNB-, 1,2-DCNE-,1,3-DCNP-, ADPN-, BZMN-, FMN-, PhCN-, and CH₃CN-Modifiedcis-1,4-Polybutadiene vs. Unmodified cis-1,4-Polybutadiene

The cis-1,4-polybutadiene samples produced in Examples 1-10 wereevaluated in a rubber compound filled with carbon black. Thecompositions of the vulcanizates are presented in Table 2, wherein thenumbers are expressed as parts by weight per hundred parts by weight oftotal rubber (phr).

TABLE 2 COMPOSITIONS OF RUBBER VULCANIZATES PREPARED FROMCIS-1,4-POLYBUTADIENE Ingredient Amount (phr) cis-1,4-Polybutadienesample 80 Polyisoprene 20 Carbon black 50 Oil 10 Wax 2 Antioxidant 1Zinc oxide 2.5 Stearic acid 2 Accelerators 1.3 Sulfur 1.5 Total 170.3

The Mooney viscosity (ML₁₋₄) of the uncured rubber compound wasdetermined at 130° C. by using a Alpha Technologies Mooney viscometerwith a large rotor, a one-minute warm-up time, and a four-minute runningtime. The Payne effect data (ΔG′) and hysteresis data (tan δ) of thevulcanizates were obtained from a dynamic strain-sweep experiment, whichwas conducted at 50° C. and 15 Hz with strain sweeping from 0.1% to 20%.ΔG′ is the difference between G′ at 0.1% strain and G′ at 20% strain.The physical properties of the vulcanizates are summarized in Table 3.In FIG. 2, the tan δ data are plotted against the compound Mooneyviscosities.

TABLE 3 PHYSICAL PROPERTIES OF RUBBER VULCANIZATES PREPARED FROMCIS-1,4-POLYBUTADIENE Example No. Example 11 Example 12 Example 13Example 14 Example 15 Example 16 Polymer used Example 1 Example 2Example 3 Example 4 Example 5 Example 6 Polymer type unmodifiedunmodified 1,2-DCNB- 1,2-DCNE- 1,3-DCNP- ADPN- modified modifiedmodified modified Compound 48.4 62.1 61.0 62.6 49.5 49.9 ML₁₊₄ at 130°C. ΔG′ (MPa) 3.95 3.69 1.53 2.48 3.08 2.30 tanδ at 50° C., 0.142 0.1300.0946 0.108 0.127 0.120 3% strain Example No. Example 19 Example 20Example 17 Example 18 (Comparative) (Comparative) Polymer used Example 7Example 8 Example 9 Example 10 Polymer type BZMN-modified FMN-modifiedPhCN-modified CH₃-modified Compound 51.9 75.6 49.7 50.0 ML₁₊₄ at 130° C.ΔG′ (MPa) 2.59 1.95 3.46 3.90 tanδ at 50° C., 0.123 0.106 0.133 0.137 3%strain

As can be seen in Table 3 and FIG. 2, the 1,2-DCNB-, 1,2-DCNE-,1,3-DCNP-, ADPN-, BZMN-, and FMN-modified cis-1,4-polybutadiene samplesgive lower tan δ than the unmodified polymer, indicating that themodification of cis-1,4-polybutadiene with 1,2-DCNB, 1,2-DCNE, 1,3-DCNP,ADPN, BZMN, or FMN reduces hysteresis. The 1,2-DCNB-, 1,2-DCNE-,1,3-DCNP-, ADPN-, BZMN-, and FMN-modified cis-1,4-polybutadiene samplesalso give lower ΔG′ than the unmodified polymer, indicating that thePayne Effect has been reduced due to the stronger interaction betweenthe modified polymer and carbon black. In contrast, both PhCN- andCH₃CN-modified cis-1,4-polybutadiene samples provide no or marginalreduction in hysteresis and the Payne effect as compared to theunmodified polymer.

Example 21 Synthesis of Unmodified Poly(styrene-co-butadiene)

To a 5-gallon nitrogen-purged reactor equipped with turbine agitatorblades were added 5100 g of hexane, 1278 g of 33.0 wt % styrene inhexane, and 7670 g of 22.0 wt % 1,3-butadiene in hexane. To the reactorwere charged 11.98 ml of 1.6M n-butyllithium in hexane and 3.95 ml of1.6M 2,2-bis(2′-tetrahydrofuryl)propane in hexane. The batch was heatedby applying hot water to the reactor jacket. Once the batch temperaturereached 50° C., the reactor jacket was cooled with cold water.

Ninety minutes after the addition of the catalyst, about 420 g of theresulting living polymer cement was transferred from the reactor into anitrogen-purged bottle and quenched by addition of 3 ml of 12 wt %2,6-di-tert-butyl-4-methylphenol solution in isopropanol. The resultingmixture was coagulated with 2 liters of isopropanol containing 0.5 g of2,6-di-tert-butyl-4-methylphenol and then drum-dried. The ¹H NMRanalysis of the polymer indicated that the polymer had a styrene contentof 21.0 wt % and a 1,2-linkage (butadiene mer unit) of 55.5%.

The cold-flow resistance of the unmodified poly(styrene-co-butadiene)was measured by using a Scott plasticity tester. The procedure issimilar to that described in Example 1, except that the residual gauge(i.e., sample thickness) was measured at 30 minutes after a 5-kg loadwas applied to the sample.

The properties of the resulting unmodified poly(styrene-co-butadiene)are summarized in Table 4.

TABLE 4 PHYSICAL PROPERTIES OF POLY(STYRENE-CO-BUTADIENE) Example No.Example 25 Example 26 Example 21 Example 22 Example 23 Example 24(comparative) (comparative) Polymer type unmodified unmodified 1,2-DCNB-ADPN- PhCN- CH₃CN- modified modified modified modified ML₁₊₄ at 100° C.13.6 97.2 63.6 46.1 20.2 24.4 M_(n) 116,600 257,500 175,500 150,400127,100 129,600 M_(w) 120,200 282,100 224,900 194,100 142,500 148,300M_(w)/M_(n) 1.03 1.10 1.28 1.29 1.12 1.14 % styrene 20.7 20.0 20.7 20.720.7 20.7 % 1,2 55.5 55.9 55.5 55.5 55.5 55.5 Cold-flow gauge 2.42 4.594.61 3.78 2.95 2.90 (mm at 30 min.)

Example 22 Synthesis of Unmodified Poly(styrene-co-butadiene)

To a 2-gallon nitrogen-purged reactor equipped with turbine agitatorblades was added 1595 g of hexane, 400 g of 34.0 wt % styrene in hexane,and 2440 g of 22.3 wt % 1,3-butadiene in hexane. To the reactor wascharged 1.70 ml of 1.6M n-butyllithium in hexane and 0.56 mL of 1.6M2,2-bis(2′-tetrahydrofuryl)propane in hexane. The batch was heated byapplying hot water to the reactor jacket. Once the batch temperaturereached 50° C., the reactor jacket was cooled with cold water. About 2.5hours after the addition of the catalyst, the polymerization mixture wasquenched with 30 ml of 12 wt % 2,6-di-tert-butyl-4-methylphenol solutionin isopropanol, coagulated with 12 liters of isopropanol containing 5 gof 2,6-di-tert-butyl-4-methylphenol, and then drum-dried. The propertiesof the resulting unmodified SBR are summarized in Table 4.

Example 23 Synthesis of Poly(styrene-co-butadiene) Modified with1,2-Dicyanobenzene (1,2-DCNB)

About 333 g of the living polymer cement as synthesized in Example 21was transferred from the reactor to a nitrogen-purged bottle, followedby addition of 2.52 ml of 0.165M 1,2-dicyanobenzene (1,2-DCNB) intoluene. The bottle was tumbled for 30 minutes in a water bathmaintained at 65° C. The resulting polymer cement was quenched with 3 mlof 12 wt % 2,6-di-tert-butyl-4-methylphenol solution in isopropanol,coagulated with 2 liters of isopropanol containing 0.5 g of2,6-di-tert-butyl-4-methylphenol, and then drum-dried. The properties ofthe resulting 1,2-DCNB-modified polymer are summarized in Table 4.

Example 24 Synthesis of Poly(styrene-co-butadiene) Modified withAdiponitrile (ADPN)

About 335 g of the living polymer cement as synthesized in Example 21was transferred from the reactor to a nitrogen-purged bottle, followedby addition of 0.98 ml of 0.427M adiponitrile (ADPN) in toluene. Thebottle was tumbled for 30 minutes in a water bath maintained at 65° C.The resulting polymer cement was quenched with 3 ml of 12 wt %2,6-di-tert-butyl-4-methylphenol solution in isopropanol, coagulatedwith 2 liters of isopropanol containing 0.5 g of2,6-di-tert-butyl-4-methylphenol, and then drum-dried. The properties ofthe resulting ADPN-modified polymer are summarized in Table 4.

Example 25 Synthesis of Poly(styrene-co-butadiene) Modified withBenzonitrile (PhCN)

About 314 g of the living polymer cement as synthesized in Example 21was transferred from the reactor to a nitrogen-purged bottle, followedby addition of 0.78 ml of 0.500M benzonitrile (PhCN) in toluene. Thebottle was tumbled for 30 minutes in a water bath maintained at 65° C.The resulting polymer cement was quenched with 3 ml of 12 wt %2,6-di-tert-butyl-4-methylphenol solution in isopropanol, coagulatedwith 2 liters of isopropanol containing 0.5 g of2,6-di-tert-butyl-4-methylphenol, and then drum-dried. The properties ofthe resulting PhCN-modified polymer are summarized in Table 4.

Example 26 Synthesis of Poly(styrene-co-butadiene) Modified withAcetonitrile (CH₃CN)

About 319 g of the living polymer cement as synthesized in Example 21was transferred from the reactor to a nitrogen-purged bottle, followedby addition of 0.80 ml of 0.500M acetonitrile (CH₃CN) in toluene. Thebottle was tumbled for 30 minutes in a water bath maintained at 65° C.The resulting polymer cement was quenched with 3 ml of 12 wt %2,6-di-tert-butyl-4-methylphenol solution in isopropanol, coagulatedwith 2 liters of isopropanol containing 0.5 g of2,6-di-tert-butyl-4-methylphenol, and then drum-dried. The properties ofthe resulting CH₃CN-modified polymer are summarized in Table 4.

In FIG. 3, the cold-flow resistance of the poly(styrene-co-butadiene)samples synthesized in Examples 15-20 is plotted against the polymerMooney viscosity. The data indicate that, at the same polymer Mooneyviscosity, the 1,2-DCNB- and ADPN-modified poly(styrene-co-butadiene)samples show higher residual cold-flow gauge values and accordinglybetter cold-flow resistance than the unmodified polymer. In contrast,both PhCN- and CH₃CN-modified poly(styrene-co-butadiene) samples provideno or marginal improvement in cold-flow resistance as compared to theunmodified polymer.

Examples 27-32 Compounding Evaluation of 1,2-DCNB-, ADPN-, PhCN- andCH₃CN-Modified Poly(styrene-co-butadiene) versus UnmodifiedPoly(styrene-co-butadiene)

The poly(styrene-co-butadiene) samples produced in Examples 21-26 wereevaluated in a rubber compound filled with carbon black. Thecompositions of the vulcanizates are presented in Table 5, wherein thenumbers are expressed as parts by weight per hundred parts by weight oftotal rubber (phr).

TABLE 5 COMPOSITIONS OF RUBBER VULCANIZATES PREPARED FROMPOLY(STYRENE-CO-BUTADIENE) Ingredient Amount (phr) SBR sample 100 Carbonblack 50 Oil 10 Wax 2 Antioxidant 0.95 Zinc oxide 2.5 Stearic acid 2Accelerators 1.3 Sulfur 1.5 Total 170.25

The Payne effect data (ΔG′) and hysteresis data (tan δ) of thevulcanizates were obtained from a dynamic strain-sweep experiment, whichwas conducted at 60° C. and 10 Hz with strain sweeping from 0.25% to15%. ΔG′ is the difference between G′ at 0.25% strain and G′ at 15%strain. The physical properties of the vulcanizates are summarized inTable 6. In FIG. 4, the tan δ data are plotted against the compoundMooney viscosities.

TABLE 6 PHYSICAL PROPERTIES OF RUBBER VULCANIZATES PREPARED FROMPOLY(STYRENE- CO-BUTADIENE) Example No. Example Example Example ExampleExample 31 Example 32 27 28 29 30 (Comparative) (Comparative) Polymerused Example 21 Example 22 Example 23 Example 24 Example 25 Example 26Polymer type unmodified unmodified 1,2-DCNB- ADPN- PhCN-modifiedCH₃-modified modified modified Compound 21.4 86.0 50.1 39.6 28.9 26.5ML₁₊₄ at 130° C. ΔG′ (MPa) 4.16 1.71 0.65 0.89 1.39 2.35 tanδ at 60° C.,0.241 0.144 0.112 0.138 0.161 0.200 5% strain

As can be seen in Table 6 and FIG. 4, the 1,2-DCNB- and ADPN-modifiedpoly(styrene-co-butadiene) samples give significantly lower tan δ thanthe unmodified polymer, indicating that the modification ofpoly(styrene-co-butadiene) with 1,2-DCNB and ADPN reduces hysteresis.The 1,2-DCNB- and ADPN-modified poly(styrene-co-butadiene) samples alsogive significantly lower ΔG′ than the unmodified polymer, indicatingthat the Payne Effect has been reduced due to the interaction betweenthe modified polymer and carbon black. In contrast, both PhCN- andCH₃CN-modified poly(styrene-co-butadiene) samples provide only smallreduction in hysteresis and the Payne effect as compared to theunmodified polymer.

Various modifications and alterations that do not depart from the scopeand spirit of this invention will become apparent to those skilled inthe art. This invention is not to be duly limited to the illustrativeembodiments set forth herein.

What is claimed is:
 1. A functionalized polymer prepared by the stepsof: (i) polymerizing monomer to form a reactive polymer; and (ii)reacting the polymer with a polycyano compound.
 2. A tire componentprepared by employing the functionalized polymer of claim
 1. 3. Avulcanizable composition comprising: the functionalized polymer of claim1, a filler, and a curative.
 4. A functionalized polymer defined by atleast one of the formulae:

where π is a polymer chain and R¹ is a divalent organic group.
 5. Thepolymer of claim 4, where π is a cis-1,4-polydiene chain having acis-1,4-linkage content that is greater than 90%.
 6. The polymer ofclaim 4, where π includes a polydiene having a cis-1,4-linkage contentof from about 10% to about 60%, and where π optionally includes merunits deriving from monomer copolymerizable with conjugated dienemonomer.
 7. A functionalized polymer defined by at least one of theformulae:

where π is a polymer chain and R¹ is a divalent organic group.
 8. Thepolymer of claim 7, where π is a cis-1,4-polydiene chain having acis-1,4-linkage content that is greater than 90%.
 9. The polymer ofclaim 7, where π includes a polydiene having a cis-1,4-linkage contentof from about 10% to about 60%, and where π optionally includes merunits deriving from monomer copolymerizable with conjugated dienemonomer.
 10. A tire component prepared from a polymer of claim
 7. 11.The tire component of claim 10, where the tire component is a tiretread.
 12. A method for preparing a functionalized polymer, the methodcomprising the steps of: (i) polymerizing monomer to form a reactivepolymer, where said step of polymerizing employs a lanthanide-basedcatalyst and where the lanthanide-based catalyst includes (a) alanthanide-containing compound, (b) an alkylating agent, and (c) ahalogen source; and (ii) reacting the reactive polymer with a polycyanocompound.
 13. The method of claim 12, where the alkylating agentincludes an aluminoxane and an organoaluminum compound represented bythe formula AlR_(n)X_(3-n), where each R, which may be the same ordifferent, is a monovalent organic group that is attached to thealuminum atom via a carbon atom, where each X, which may be the same ordifferent, is a hydrogen atom, a halogen atom, a carboxylate group, analkoxide group, or an aryloxide group, and where n is an integer of 1 to3.
 14. The method of claim 13, where said step of polymerizing monomertakes place within a polymerization mixture including less than 20% byweight of organic solvent.